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Flagg MP, Lam B, Lam DK, Le TM, Kao A, Slaiwa YI, Hampton RY. Exploring the "misfolding problem" by systematic discovery and analysis of functional-but-degraded proteins. Mol Biol Cell 2023; 34:ar125. [PMID: 37729018 PMCID: PMC10848938 DOI: 10.1091/mbc.e23-06-0248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 09/22/2023] Open
Abstract
In both health and disease, the ubiquitin-proteasome system (UPS) degrades point mutants that retain partial function but have decreased stability compared with their wild-type counterparts. This class of UPS substrate includes routine translational errors and numerous human disease alleles, such as the most common cause of cystic fibrosis, ΔF508-CFTR. Yet, there is no systematic way to discover novel examples of these "minimally misfolded" substrates. To address that shortcoming, we designed a genetic screen to isolate functional-but-degraded point mutants, and we used the screen to study soluble, monomeric proteins with known structures. These simple parent proteins yielded diverse substrates, allowing us to investigate the structural features, cytotoxicity, and small-molecule regulation of minimal misfolding. Our screen can support numerous lines of inquiry, and it provides broad access to a class of poorly understood but biomedically critical quality-control substrates.
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Affiliation(s)
- Matthew P. Flagg
- Division of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093
| | - Breanna Lam
- Division of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093
| | - Darren K. Lam
- Division of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093
| | - Tiffany M. Le
- Division of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093
| | - Andy Kao
- Division of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093
| | - Yousif I. Slaiwa
- Division of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093
| | - Randolph Y. Hampton
- Division of Biological Sciences, the Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093
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2
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Akrout F, Achour A, Tops CMJ, Gallon R, Meddeb R, Achoura S, Ben Rekaya M, Hamdeni E, Rammeh S, Chkili R, Mansouri N, Belguith N, Mrad R. Constitutional mismatch repair deficiency syndrome with atypical features caused by a homozygous MLH1 missense variant (c.1918C>A, p.(Pro640Thr)): a case report. Front Oncol 2023; 13:1195814. [PMID: 37664053 PMCID: PMC10471184 DOI: 10.3389/fonc.2023.1195814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 07/24/2023] [Indexed: 09/05/2023] Open
Abstract
Constitutional mismatch repair deficiency (CMMRD) syndrome is a rare autosomal recessive genetic disorder caused by biallelic germline mutations in one of the mismatch repair genes. Carriers are at exceptionally high risk for developing, typically in early life, hematological and brain malignancies, as well as cancers observed in Lynch syndrome. We report a homozygous MLH1 missense variant (c.1918C>A p.(Pro640Thr)) in a Tunisian patient with CMMRD syndrome and a family history of early-age colorectal cancer. The proband presented initially with colonic oligopolyposis and adenosquamous carcinoma of the caecum. He later developed several malignancies, including undifferentiated carcinoma of the parotid, grade 4 IDH-mutant astrocytoma, and ampulla of Vater adenocarcinoma. The patient was older than typical for this disease and had a remarkably prolonged survival despite developing four distinct aggressive malignancies. The current report highlights the challenges in assessing the pathogenicity of the identified variant and the remarkable phenotypic diversity in CMMRD.
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Affiliation(s)
- Firas Akrout
- Department of Neurosurgery, Military Hospital of Tunis, Tunis, Tunisia
- Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Ahlem Achour
- Department of Congenital and Hereditary Diseases, Charles Nicolle Hospital, Tunis, Tunisia
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, Netherlands
- Laboratory of Human Genetics, Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Carli M. J. Tops
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, Netherlands
| | - Richard Gallon
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Rym Meddeb
- Department of Congenital and Hereditary Diseases, Charles Nicolle Hospital, Tunis, Tunisia
- Laboratory of Human Genetics, Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Sameh Achoura
- Department of Neurosurgery, Military Hospital of Tunis, Tunis, Tunisia
- Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Mariem Ben Rekaya
- Research Unit of Onco-theranostic Biomarkers UR17ES15, Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
- Department of Pathology, Charles Nicolle Hospital, Tunis, Tunisia
| | - Emna Hamdeni
- Research Unit of Onco-theranostic Biomarkers UR17ES15, Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Soumaya Rammeh
- Research Unit of Onco-theranostic Biomarkers UR17ES15, Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
- Department of Pathology, Charles Nicolle Hospital, Tunis, Tunisia
| | - Ridha Chkili
- Department of Neurosurgery, Military Hospital of Tunis, Tunis, Tunisia
- Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Nada Mansouri
- Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
- Department of Pathology, Military Hospital of Tunis, Tunis, Tunisia
| | - Neila Belguith
- Department of Congenital and Hereditary Diseases, Charles Nicolle Hospital, Tunis, Tunisia
- Laboratory of Human Molecular Genetics, Faculty of Medicine of Sfax, University of Sfax, Sfax, Tunisia
| | - Ridha Mrad
- Department of Congenital and Hereditary Diseases, Charles Nicolle Hospital, Tunis, Tunisia
- Laboratory of Human Genetics, Faculty of Medicine of Tunis, University of Tunis El Manar, Tunis, Tunisia
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3
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Abildgaard AB, Nielsen SV, Bernstein I, Stein A, Lindorff-Larsen K, Hartmann-Petersen R. Lynch syndrome, molecular mechanisms and variant classification. Br J Cancer 2023; 128:726-734. [PMID: 36434153 PMCID: PMC9978028 DOI: 10.1038/s41416-022-02059-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 10/31/2022] [Accepted: 11/02/2022] [Indexed: 11/27/2022] Open
Abstract
Patients with the heritable cancer disease, Lynch syndrome, carry germline variants in the MLH1, MSH2, MSH6 and PMS2 genes, encoding the central components of the DNA mismatch repair system. Loss-of-function variants disrupt the DNA mismatch repair system and give rise to a detrimental increase in the cellular mutational burden and cancer development. The treatment prospects for Lynch syndrome rely heavily on early diagnosis; however, accurate diagnosis is inextricably linked to correct clinical interpretation of individual variants. Protein variant classification traditionally relies on cumulative information from occurrence in patients, as well as experimental testing of the individual variants. The complexity of variant classification is due to (1) that variants of unknown significance are rare in the population and phenotypic information on the specific variants is missing, and (2) that individual variant testing is challenging, costly and slow. Here, we summarise recent developments in high-throughput technologies and computational prediction tools for the assessment of variants of unknown significance in Lynch syndrome. These approaches may vastly increase the number of interpretable variants and could also provide important mechanistic insights into the disease. These insights may in turn pave the road towards developing personalised treatment approaches for Lynch syndrome.
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Affiliation(s)
- Amanda B Abildgaard
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Sofie V Nielsen
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
| | - Inge Bernstein
- Department of Surgical Gastroenterology, Aalborg University Hospital, Aalborg, Denmark
- Institute of Clinical Medicine, Aalborg University Hospital, Aalborg University, Aalborg, Denmark
| | - Amelie Stein
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kresten Lindorff-Larsen
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
| | - Rasmus Hartmann-Petersen
- The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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4
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Rath A, Radecki AA, Rahman K, Gilmore RB, Hudson JR, Cenci M, Tavtigian SV, Grady JP, Heinen CD. A calibrated cell-based functional assay to aid classification of MLH1 DNA mismatch repair gene variants. Hum Mutat 2022; 43:2295-2307. [PMID: 36054288 PMCID: PMC9772141 DOI: 10.1002/humu.24462] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 06/21/2022] [Accepted: 08/30/2022] [Indexed: 01/25/2023]
Abstract
Functional assays provide important evidence for classifying the disease significance of germline variants in DNA mismatch repair genes. Numerous laboratories, including our own, have developed functional assays to study mismatch repair gene variants. However, previous assays are limited due to the model system employed, the manner of gene expression, or the environment in which function is assessed. Here, we developed a human cell-based approach for testing the function of variants of uncertain significance (VUS) in the MLH1 gene. Using clustered regularly interspaced short palindromic repeats gene editing, we knocked in MLH1 VUS into the endogenous MLH1 loci in human embryonic stem cells. We examined their impact on RNA and protein, including their ability to prevent microsatellite instability and instigate a DNA damage response. A statistical clustering analysis determined the range of functions associated with known pathogenic or benign variants, and linear regression was performed using existing odds in favor of pathogenicity scores for these control variants to calibrate our functional assay results. By converting the functional outputs into a single odds in favor of pathogenicity score, variant classification expert panels can use these results to readily reassess these VUS. Ultimately, this information will guide proper diagnosis and disease management for suspected Lynch syndrome patients.
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Affiliation(s)
- Abhijit Rath
- Center for Molecular Oncology, UConn Health, Farmington, CT
| | | | - Kaussar Rahman
- Center for Molecular Oncology, UConn Health, Farmington, CT
| | - Rachel B. Gilmore
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT
| | - Jonathan R. Hudson
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT
| | - Matthew Cenci
- Center for Molecular Oncology, UConn Health, Farmington, CT
| | - Sean V. Tavtigian
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT
| | - James P. Grady
- Connecticut Institute for Clinical and Translational Science, UConn Health, Farmington, CT
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5
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Mahdouani M, Ben Ahmed S, Hmila F, Rais H, Ben Sghaier R, Saad H, Ben Said M, Masmoudi S, Hmida D, Brieger A, Zeuzem S, Saad A, Gribaa M, Plotz G. Functional characterization of MLH1 missense variants unveils mechanisms of pathogenicity and clarifies role in cancer. PLoS One 2022; 17:e0278283. [PMID: 36454741 PMCID: PMC9714755 DOI: 10.1371/journal.pone.0278283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/28/2022] [Indexed: 12/05/2022] Open
Abstract
Lynch syndrome is a heritable condition caused by a heterozygous germline inactivating mutation of the DNA mismatch repair (MMR) genes, most commonly the MLH1 gene. However, one third of the identified alterations are missense variants, for which the clinical significance is unclear in many cases. We have identified three MLH1 missense alterations (p.(Glu736Lys), p.(Pro640Thr) and p.(Leu73Pro)) in six individuals from large Tunisian families. For none of these alterations, a classification of pathogenicity was available, consequently diagnosis, predictive testing and targeted surveillance in affected families was impossible. We therefore performed functional laboratory testing using a system testing stability as well as catalytic activity that includes clinically validated reference variants. Both p.(Leu73Pro) and p.(Pro640Thr) were found to be non-functional due to severe defects in protein stability and catalytic activity. In contrast, p.(Glu736Lys) was comparable to the wildtype protein and therefore considered a neutral substitution. Analysis of residue conservation and of the structural roles of the substituted residues corroborated these findings. In conjunction with the available clinical data, two variants fulfil classification criteria for class 4 "likely pathogenic". The findings of this work clarify the mechanism of pathogenicity of two unclear MLH1 variants and enables predictive testing and targeted surveillance in members of carrier families worldwide.
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Affiliation(s)
- Marwa Mahdouani
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Higher Institute of Biotechnology of Monastir, University of Monastir, Monastir, Tunisia
| | - Slim Ben Ahmed
- Department of Oncology, Farhat Hached University Hospital, Sousse, Tunisia
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
| | - Fahmi Hmila
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
- Department of General and Digestive Surgery, Farhat Hached University Hospital, Sousse, Tunisia
| | - Henda Rais
- Medical Service, Salah Azaiez Institute, Tunis, Tunisia
| | - Rihab Ben Sghaier
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Higher Institute of Biotechnology of Monastir, University of Monastir, Monastir, Tunisia
| | - Hanene Saad
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Higher Institute of Biotechnology of Monastir, University of Monastir, Monastir, Tunisia
| | - Mariem Ben Said
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, Sfax, Tunisia
| | - Saber Masmoudi
- Laboratory of Molecular and Cellular Screening Processes, Centre of Biotechnology of Sfax, Sfax, Tunisia
| | - Dorra Hmida
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
| | - Angela Brieger
- Biomedical Research Laboratory, Department of Internal Medicine 1, University Hospital, Goethe University, Frankfurt am Main, Germany
| | - Stefan Zeuzem
- Biomedical Research Laboratory, Department of Internal Medicine 1, University Hospital, Goethe University, Frankfurt am Main, Germany
| | - Ali Saad
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
| | - Moez Gribaa
- Laboratory of Human Cytogenetics, Molecular Genetics and Reproductive Biology, Farhat Hached University Hospital, Sousse, Tunisia
- Faculty of Medicine Ibn El Jazzar of Sousse, University of Sousse, Sousse, Tunisia
| | - Guido Plotz
- Biomedical Research Laboratory, Department of Internal Medicine 1, University Hospital, Goethe University, Frankfurt am Main, Germany
- * E-mail:
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6
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Bosch DE, Yeh MM, Salipante SJ, Jacobson A, Cohen SA, Konnick EQ, Paulson VA. Isolated MLH1 Loss by Immunohistochemistry Because of Benign Germline MLH1 Polymorphisms. JCO Precis Oncol 2022; 6:e2200227. [PMID: 36044719 PMCID: PMC9489174 DOI: 10.1200/po.22.00227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Mismatch repair (MMR) immunohistochemistry (IHC) is frequently used to inform prognosis, select (immuno-)therapy, and identify patients for heritable cancer syndrome testing. However, false-negative and false-positive MMR IHC interpretations have been described.
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Affiliation(s)
- Dustin E Bosch
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, WA.,Department of Pathology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA
| | - Matthew M Yeh
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, WA
| | - Stephen J Salipante
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, WA
| | - Angela Jacobson
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, WA
| | - Stacey A Cohen
- Division of Medical Oncology, Department of Medicine, University of Washington School of Medicine, Seattle, WA.,Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA
| | - Eric Q Konnick
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, WA
| | - Vera A Paulson
- Department of Laboratory Medicine and Pathology, University of Washington School of Medicine, Seattle, WA
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7
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Alim I, Loke J, Yam S, Templeton AS, Newcomb P, Lindor NM, Pai RK, Jenkins MA, Buchanan DD, Gallinger S, Klugman S, Ostrer H. Cancer Risk C (CR-C), a functional genomics test is a sensitive and rapid test for germline mismatch repair deficiency. Genet Med 2022; 24:1821-1830. [PMID: 35616648 PMCID: PMC10072225 DOI: 10.1016/j.gim.2022.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 04/29/2022] [Accepted: 05/02/2022] [Indexed: 10/18/2022] Open
Abstract
PURPOSE Heritable pathogenic variants in the DNA mismatch repair (MMR) pathway cause Lynch syndrome, a condition that significantly increases risk of colorectal and other cancers. At least half of individuals tested using gene panel sequencing have a variant of uncertain significance or no variant identified leading to no diagnosis. To fill this diagnostic gap, we developed Cancer Risk C (CR-C), a flow variant assay test. METHODS In response to treatment with an alkylating agent, individual assays of the nuclear translocation of MLH1, MSH2, BARD1, PMS2, and BRCA2 proteins and the nuclear phosphorylation of the ATM and ATR proteins distinguished pathogenic/likely pathogenic (P/LP) from benign/likely benign variants in MMR genes. RESULTS A risk classification score based on MLH1, MSH2, and ATR assays was 100% sensitive and 98% specific. Causality of MMR P/LP variants was shown through gene editing and rescue. In individuals with suspected Lynch syndrome but no P/LP, CR-C identified most (73%) as having germline MMR defects. Direct comparison of CR-C on matched blood samples and lymphoblastoid cell lines yielded comparable results (r2 > 0.9). CONCLUSION For identifying germline MMR defects, CR-C provides augmentation to traditional panel sequencing through greater accuracy, shorter turnaround time (48 hours), and performance on blood with minimal sample handling.
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Affiliation(s)
| | - Johnny Loke
- Morgan & Mendel Genomics, Inc, Bronx, NY; Albert Einstein College of Medicine, Bronx, NY
| | - Sarah Yam
- Morgan & Mendel Genomics, Inc, Bronx, NY
| | | | | | | | | | - Mark A Jenkins
- The University of Melbourne, Melbourne, Victoria, Australia
| | | | | | - Susan Klugman
- Albert Einstein College of Medicine, Bronx, NY; Montefiore Medical Center, Bronx, NY
| | - Harry Ostrer
- Morgan & Mendel Genomics, Inc, Bronx, NY; Albert Einstein College of Medicine, Bronx, NY; Montefiore Medical Center, Bronx, NY.
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8
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Fischer CG, Pallavajjala A, Jiang L, Anagnostou V, Tao J, Adams E, Eshleman JR, Gocke CD, Lin MT, Platz EA, Xian RR. Artificial intelligence-assisted serial analysis of clinical cancer genomics data identifies changing treatment recommendations and therapeutic targets. Clin Cancer Res 2022; 28:2361-2372. [PMID: 35312750 DOI: 10.1158/1078-0432.ccr-21-4061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 02/15/2022] [Accepted: 03/17/2022] [Indexed: 11/16/2022]
Abstract
PURPOSE Given the pace of predictive biomarker and targeted therapy development, it is unknown if repeat annotation of the same next-generation sequencing data can identify additional clinically actionable targets that could be therapeutically leveraged. In this study, we sought to determine the predictive yield of serial re-analysis of clinical tumor sequencing data. EXPERIMENTAL DESIGN Using artificial intelligence (AI)-assisted variant annotation, we retrospectively re-analyzed sequencing data from 2,219 cancer patients from a single academic medical center at 3-month intervals totaling 9 months in 2020. The yield of serial re-analysis was assessed by the proportion of patients with improved strength of therapeutic recommendations. RESULTS 1,775 patients (80%) had {greater than or equal to}1 potentially clinically actionable mutation at baseline, including 243 (11%) patients who had an alteration targeted by an FDA-approved drug for their cancer type. By month nine, the latter increased to 458 (21%) patients mainly due to a single pan-cancer agent directed against tumors with high tumor mutation burden. Within this timeframe, 67 new therapies became available and 45 were no longer available. Variant pathogenicity classifications also changed leading to changes in treatment recommendations for 124 patients (6%). CONCLUSIONS Serial re-annotation of tumor sequencing data improved the strength of treatment recommendations (based on level of evidence) in a mixed cancer cohort and showed substantial changes in available therapies and variant classifications. These results suggest a role for repeat analysis of tumor sequencing data in clinical practice, which can be streamlined with AI support.
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Affiliation(s)
| | | | - LiQun Jiang
- Johns Hopkins Medical Institutions, United States
| | - Valsamo Anagnostou
- Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jessica Tao
- Johns Hopkins Medical Institutions, United States
| | - Emily Adams
- Johns Hopkins Medical Institutions, Baltimore, MD, United States
| | | | | | - Ming-Tseh Lin
- The Johns Hopkins School of Medicine, Baltimore, United States
| | - Elizabeth A Platz
- Johns Hopkins Bloomberg School of Public Health, Baltimore, United States
| | - Rena R Xian
- Johns Hopkins Medical Institutions, Baltimore, MD, United States
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9
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Nagabhushana P, Kumari S, Rohilla M, Srinivasan R, Arora A, Rastogi P. Discordant immunohistochemistry in an unusual MLH1 gene variant in a case of Lynch syndrome. Gynecol Oncol Rep 2021; 37:100854. [PMID: 34504932 PMCID: PMC8416636 DOI: 10.1016/j.gore.2021.100854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/20/2021] [Accepted: 08/24/2021] [Indexed: 02/07/2023] Open
Abstract
Immunohistochemistry for mismatch repair proteins and microsatellite instability testing are recommended screening methods for Lynch syndrome. They have a good sensitivity and specificity, allowing for directed genetic testing and diagnosis. We report a case of Lynch syndrome with retained MMR protein expression who later showed an MLH1 gene variant on genetic testing (Next Generation Sequencing) requested because of the clinical presentation of metachronous colonic and endometrial carcinoma. This report makes the case for strong clinical suspicion and directed genetic testing despite initial screen negative results.
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Affiliation(s)
| | - Snigdha Kumari
- Department of Obstetrics and Gynecology, PGIMER, Chandigarh, India
| | - Minakshi Rohilla
- Department of Obstetrics and Gynecology, PGIMER, Chandigarh, India
| | - Radhika Srinivasan
- Department of Cytology and Gynecologic Pathology, PGIMER, Chandigarh, India
| | - Aashima Arora
- Department of Obstetrics and Gynecology, PGIMER, Chandigarh, India
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10
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Leelatian N, Hong CS, Bindra RS. The Role of Mismatch Repair in Glioblastoma Multiforme Treatment Response and Resistance. Neurosurg Clin N Am 2021; 32:171-180. [PMID: 33781500 DOI: 10.1016/j.nec.2020.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Mismatch repair (MMR) is a highly conserved DNA repair pathway that is critical for the maintenance of genomic integrity. This pathway targets base substitution and insertion-deletion mismatches, which primarily arise from replication errors that escape DNA polymerase proof-reading function. Here, the authors review key concepts in the molecular mechanisms of MMR in response to alkylation damage, approaches to detect MMR status in the clinic, and the clinical relevance of this pathway in glioblastoma multiforme treatment response and resistance.
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Affiliation(s)
- Nalin Leelatian
- Department of Pathology, Yale School of Medicine, 310 Cedar Street LH 108, New Haven, CT 06510, USA
| | - Christopher S Hong
- Department of Neurosurgery, Yale School of Medicine, 333 Cedar Street Tompkins 4, New Haven, CT 06510, USA
| | - Ranjit S Bindra
- Department of Therapeutic Radiology, Yale School of Medicine, 333 Cedar Street Hunter 2, New Haven, CT 06510, USA.
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11
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Identification of MLH2/hPMS1 dominant mutations that prevent DNA mismatch repair function. Commun Biol 2020; 3:751. [PMID: 33303966 PMCID: PMC7730388 DOI: 10.1038/s42003-020-01481-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 11/11/2020] [Indexed: 12/27/2022] Open
Abstract
Inactivating mutations affecting key mismatch repair (MMR) components lead to microsatellite instability (MSI) and cancer. However, a number of patients with MSI-tumors do not present alterations in classical MMR genes. Here we discovered that specific missense mutations in the MutL homolog MLH2, which is dispensable for MMR, confer a dominant mutator phenotype in S. cerevisiae. MLH2 mutations elevated frameshift mutation rates, and caused accumulation of long-lasting nuclear MMR foci. Both aspects of this phenotype were suppressed by mutations predicted to prevent the binding of Mlh2 to DNA. Genetic analysis revealed that mlh2 dominant mutations interfere with both Exonuclease 1 (Exo1)-dependent and Exo1-independent MMR. Lastly, we demonstrate that a homolog mutation in human hPMS1 results in a dominant mutator phenotype. Our data support a model in which yeast Mlh1-Mlh2 or hMLH1-hPMS1 mutant complexes act as roadblocks on DNA preventing MMR, unraveling a novel mechanism that can account for MSI in human cancer.
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12
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Bhai P, Kulshrestha S, Puri RD, Bijarnia Mahay S, Saxena R, Verma IC. Spectrum of mutations in genes associated with familial colorectal cancer syndrome (MLH1, MSH2, PMS2, MSH6, and APC): A not so common hereditary cancer syndrome in Indian population. Indian J Gastroenterol 2020; 39:599-607. [PMID: 33191490 DOI: 10.1007/s12664-020-01096-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 09/14/2020] [Indexed: 02/04/2023]
Abstract
Incidence of colorectal cancer (CRC) is lower in India than in other parts of the world. Approximately 5% to 10% of CRC is inherited. Hereditary non-polyposis colorectal cancer (HNPCC) syndrome and familial adenomatous polyposis (FAP) syndrome are the two known familial cancer syndromes of gastrointestinal tract, which occur due to inherited genetic predisposition. Not much is known about the molecular profile of families with inherited CRC syndromes seen in Indian population. At our institute, we have been providing genetic testing and counseling service to all the families referred to us with suspicion of inherited cancer predisposition syndrome. We analyzed 36 suspected families at our clinic. Personal and family history of cancer was obtained from the proband and appropriate genetic testing was performed in 19 patients (13 with HNPCC, 5 with FAP, and 1 with Cowden syndrome). We present here our experience and spectrum of pathogenic variants observed in this patient cohort and review on published studies describing molecular profile of Indian patients with CRC syndromes.
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Affiliation(s)
- Pratibha Bhai
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi, 110 060, India.
| | - Samarth Kulshrestha
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi, 110 060, India
| | - Ratna D Puri
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi, 110 060, India
| | - Sunita Bijarnia Mahay
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi, 110 060, India
| | - Renu Saxena
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi, 110 060, India
| | - Ishwar Chander Verma
- Institute of Medical Genetics and Genomics, Sir Ganga Ram Hospital, Rajinder Nagar, New Delhi, 110 060, India
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Kim SS, Eun JW, Choi JH, Woo HG, Cho HJ, Ahn HR, Suh CW, Baek GO, Cho SW, Cheong JY. MLH1 single-nucleotide variant in circulating tumor DNA predicts overall survival of patients with hepatocellular carcinoma. Sci Rep 2020; 10:17862. [PMID: 33082400 PMCID: PMC7576198 DOI: 10.1038/s41598-020-74494-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 09/30/2020] [Indexed: 02/07/2023] Open
Abstract
Liquid biopsy can provide a strong basis for precision medicine. We aimed to identify novel single-nucleotide variants (SNVs) in circulating tumor DNA (ctDNA) in patients with hepatocellular carcinoma (HCC). Deep sequencing of plasma-derived ctDNA from 59 patients with HCC was performed using a panel of 2924 SNVs in 69 genes. In 55.9% of the patients, at least one somatic mutation was detected. Among 25 SNVs in 12 genes, four frequently observed SNVs, MLH1 (13%), STK11 (13%), PTEN (9%), and CTNNB1 (4%), were validated using droplet digital polymerase chain reaction with ctDNA from 62 patients with HCC. Three candidate SNVs were detected in 35.5% of the patients, with a frequency of 19% for MLH1 chr3:37025749T>A, 11% for STK11 chr19:1223126C>G, and 8% for PTEN chr10:87864461C>G. The MLH1 and STK11 SNVs were also confirmed in HCC tissues. The presence of the MLH1 SNV, in combination with an increased ctDNA level, predicted poor overall survival among 107 patients. MLH1 chr3:37025749T>A SNV detection in ctDNA is feasible, and thus, ctDNA can be used to detect somatic mutations in HCC. Furthermore, the presence or absence of the MLH1 SNV in ctDNA, combined with the ctDNA level, can predict the prognosis of patients with HCC.
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Affiliation(s)
- Soon Sun Kim
- Department of Gastroenterology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Jung Woo Eun
- Department of Gastroenterology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Ji-Hye Choi
- Department of Physiology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Hyun Goo Woo
- Department of Physiology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Hyo Jung Cho
- Department of Gastroenterology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Hye Ri Ahn
- Department of Biomedical Science, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - Chul Won Suh
- Department of Biomedical Science, Ajou University Graduate School of Medicine, Suwon, Republic of Korea
| | - Geum Ok Baek
- Department of Gastroenterology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Sung Won Cho
- Department of Gastroenterology, Ajou University School of Medicine, Suwon, Republic of Korea
| | - Jae Youn Cheong
- Department of Gastroenterology, Ajou University School of Medicine, Suwon, Republic of Korea.
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14
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Pajkos M, Zeke A, Dosztányi Z. Ancient Evolutionary Origin of Intrinsically Disordered Cancer Risk Regions. Biomolecules 2020; 10:biom10081115. [PMID: 32731489 PMCID: PMC7465906 DOI: 10.3390/biom10081115] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 07/17/2020] [Accepted: 07/20/2020] [Indexed: 12/12/2022] Open
Abstract
Cancer is a heterogeneous genetic disease that alters the proper functioning of proteins involved in key regulatory processes such as cell cycle, DNA repair, survival, or apoptosis. Mutations often accumulate in hot-spots regions, highlighting critical functional modules within these proteins that need to be altered, amplified, or abolished for tumor formation. Recent evidence suggests that these mutational hotspots can correspond not only to globular domains, but also to intrinsically disordered regions (IDRs), which play a significant role in a subset of cancer types. IDRs have distinct functional properties that originate from their inherent flexibility. Generally, they correspond to more recent evolutionary inventions and show larger sequence variations across species. In this work, we analyzed the evolutionary origin of disordered regions that are specifically targeted in cancer. Surprisingly, the majority of these disordered cancer risk regions showed remarkable conservation with ancient evolutionary origin, stemming from the earliest multicellular animals or even beyond. Nevertheless, we encountered several examples where the mutated region emerged at a later stage compared with the origin of the gene family. We also showed the cancer risk regions become quickly fixated after their emergence, but evolution continues to tinker with their genes with novel regulatory elements introduced even at the level of humans. Our concise analysis provides a much clearer picture of the emergence of key regulatory elements in proteins and highlights the importance of taking into account the modular organisation of proteins for the analyses of evolutionary origin.
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Affiliation(s)
- Mátyás Pajkos
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter stny 1/c, H-1117 Budapest, Hungary;
| | - András Zeke
- Research Centre for Natural Sciences, Magyar tudósok körútja 2, H-1117 Budapest, Hungary;
| | - Zsuzsanna Dosztányi
- Department of Biochemistry, ELTE Eötvös Loránd University, Pázmány Péter stny 1/c, H-1117 Budapest, Hungary;
- Correspondence:
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15
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Cervelli T, Lodovichi S, Bellè F, Galli A. Yeast-based assays for the functional characterization of cancer-associated variants of human DNA repair genes. MICROBIAL CELL 2020; 7:162-174. [PMID: 32656256 PMCID: PMC7328678 DOI: 10.15698/mic2020.07.721] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Technological advances are continuously revealing new genetic variants that are often difficult to interpret. As one of the most genetically tractable model organisms, yeast can have a central role in determining the consequences of human genetic variation. DNA repair gene mutations are associated with many types of cancers, therefore the evaluation of the functional impact of these mutations is crucial for risk assessment and for determining therapeutic strategies. Owing to the evolutionary conservation of DNA repair pathways between human cells and the yeast Saccharomyces cerevisiae, several functional assays have been developed. Here, we describe assays for variants of human genes belonging to the major DNA repair pathways divided in functional assays for human genes with yeast orthologues and human genes lacking a yeast orthologue. Human genes with orthologues can be studied by introducing the correspondent human mutations directly in the yeast gene or expressing the human gene carrying the mutations; while the only possible approach for human genes without a yeast orthologue is the heterologous expression. The common principle of these approaches is that the mutated gene determines a phenotypic alteration that can vary according to the gene studied and the domain of the protein. Here, we show how the versatility of yeast can help in classifying cancer-associated variants.
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Affiliation(s)
- Tiziana Cervelli
- Yeast Genetics and Genomics Group, Laboratory of Functional Genetics and Genomics, Institute of Clinical Physiology CNR, Via Moruzzi 1, 56125 Pisa, Italy
| | - Samuele Lodovichi
- Yeast Genetics and Genomics Group, Laboratory of Functional Genetics and Genomics, Institute of Clinical Physiology CNR, Via Moruzzi 1, 56125 Pisa, Italy
| | - Francesca Bellè
- Yeast Genetics and Genomics Group, Laboratory of Functional Genetics and Genomics, Institute of Clinical Physiology CNR, Via Moruzzi 1, 56125 Pisa, Italy
| | - Alvaro Galli
- Yeast Genetics and Genomics Group, Laboratory of Functional Genetics and Genomics, Institute of Clinical Physiology CNR, Via Moruzzi 1, 56125 Pisa, Italy
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16
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Cerretelli G, Ager A, Arends MJ, Frayling IM. Molecular pathology of Lynch syndrome. J Pathol 2020; 250:518-531. [PMID: 32141610 DOI: 10.1002/path.5422] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 03/02/2020] [Accepted: 03/03/2020] [Indexed: 12/18/2022]
Abstract
Lynch syndrome (LS) is characterised by predisposition to colorectal, endometrial, and other cancers and is caused by inherited pathogenic variants affecting the DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6, and PMS2. It is probably the most common predisposition to cancer, having an estimated prevalence of between 1/100 and 1/180. Resources such as the International Society for Gastrointestinal Hereditary Cancer's MMR gene variant database, the Prospective Lynch Syndrome Database (PLSD), and the Colon Cancer Family Register (CCFR), as well as pathological and immunological studies, are enabling advances in the understanding of LS. These include defined criteria by which to interpret gene variants, the function of MMR in the normal control of apoptosis, definition of the risks of the various cancers, and the mechanisms and pathways by which the colorectal and endometrial tumours develop, including the critical role of the immune system. Colorectal cancers in LS can develop along three pathways, including flat intramucosal lesions, which depend on the underlying affected MMR gene. This gives insights into the limitations of colonoscopic surveillance and highlights the need for other forms of anti-cancer prophylaxis in LS. Finally, it shows that the processes of autoimmunisation and immunoediting fundamentally constrain the development of tumours in LS and explain the efficacy of immune checkpoint blockade therapy in MMR-deficient tumours. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Guia Cerretelli
- Division of Pathology, Cancer Research UK Edinburgh Centre, University of Edinburgh, Edinburgh, UK
| | - Ann Ager
- Division of Infection and Immunity, School of Medicine and Systems Immunity Research Institute, Cardiff University, Cardiff, UK
| | - Mark J Arends
- Division of Pathology, Cancer Research UK Edinburgh Centre, University of Edinburgh, Edinburgh, UK
| | - Ian M Frayling
- Inherited Tumour Syndromes Research Group, Institute of Cancer & Genetics, School of Medicine, Cardiff University, Cardiff, UK
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17
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Functional Characterization of a Missense Variant of MLH1 Identified in Lynch Syndrome Pedigree. DISEASE MARKERS 2020; 2020:8360841. [PMID: 32076465 PMCID: PMC7008259 DOI: 10.1155/2020/8360841] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 12/23/2019] [Indexed: 12/30/2022]
Abstract
Lynch syndrome (LS) is the most common hereditary colorectal cancer (CRCs) inherited in an autosomal-dominant manner. Here, we reported a multigeneration Chinese family clinically diagnosed with LS according to the Amsterdam II criteria. To identify the underlying causative gene for LS in this family, whole-exome sequencing (WES) was performed. A germline missense variant (c.2054C>T:p.S685F) in exon 18 of MLH1 was successfully identified by WES. Sanger sequencing verified the results of WES and also confirmed the cosegregation of the MLH1 missense variant in all affected members of the family including two unaffected family members. Bioinformatic tools predicted the identified MLH1 variant as deleterious. Immunohistochemistry (IHC) staining showed loss of MLH1 and PMS2 protein expression. In vitro expression analysis also revealed that the identified MLH1 missense variant (c.2054C>T:p.S685F) results in reduced expression of both MLH1 and PMS2 proteins. Based on the American College of Medical Genetics and Genomics (ACMG) guidelines, the missense mutation c.2054C>T in MLH1 was classified as a “pathogenic” variant. Two unaffected family members were later recommended for colonoscopy and other important cancer diagnostic inspections every 1-2 years as both were at higher risk of LS. In conclusion, our findings widen the genotypic spectrum of MLH1 mutations responsible for LS. This study increases the phenotypic spectrum of LS which will certainly help the clinicians in diagnosing LS in multigeneration families. This study also puts emphasis on the importance of genetic counselling for the benefit of asymptomatic carriers of MMR gene variants who are at higher risk of LS.
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18
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González-Acosta M, Hinrichsen I, Fernández A, Lázaro C, Pineda M, Plotz G, Capellá G. Validation of an in Vitro Mismatch Repair Assay Used in the Functional Characterization of Mismatch Repair Variants. J Mol Diagn 2019; 22:376-385. [PMID: 31881334 DOI: 10.1016/j.jmoldx.2019.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 09/27/2019] [Accepted: 12/05/2019] [Indexed: 10/25/2022] Open
Abstract
A significant proportion of DNA-mismatch repair (MMR) variants are classified as of unknown significance, precluding diagnosis. The in vitro MMR assay is used to assess their MMR capability, likely the most important function of an MMR protein. However, the robustness of the assay, crucial for its use in the clinical setting, has been rarely evaluated. The aim of the present work was to validate an in vitro MMR assay approach to the functional characterization of MMR variants, as a first step to meeting quality standards of diagnostic laboratories. The MMR assay was optimized by testing a variety of reagents and experimental conditions. Reference materials and standard operating procedures were established. To determine the intra- and interexperimental variability of the assay and its reproducibility among centers, independent transfections of six previously characterized MLH1 variants were performed in two independent laboratories. Reagents and conditions optimal for performing the in vitro MMR assay were determined. The validated assay demonstrated no significant intra- or interexperimental variability and good reproducibility between centers. We set up a robust in vitro MMR assay that can provide relevant in vitro functional evidence for MMR variant pathogenicity assessment, eventually improving the molecular diagnosis of hereditary cancer syndromes associated with MMR deficiency.
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Affiliation(s)
- Maribel González-Acosta
- Hereditary Cancer Program, the Catalan Institute of Oncology (ICO), Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Ciber Oncología (CIBERONC) Instituto Salud Carlos III, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Inga Hinrichsen
- Biomedical Research Laboratory, Department of Internal Medicine 1, Universitätsklinikum Frankfurt, Frankfurt, Germany
| | - Anna Fernández
- Hereditary Cancer Program, the Catalan Institute of Oncology (ICO), Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Ciber Oncología (CIBERONC) Instituto Salud Carlos III, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Conxi Lázaro
- Hereditary Cancer Program, the Catalan Institute of Oncology (ICO), Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Ciber Oncología (CIBERONC) Instituto Salud Carlos III, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Marta Pineda
- Hereditary Cancer Program, the Catalan Institute of Oncology (ICO), Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Ciber Oncología (CIBERONC) Instituto Salud Carlos III, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Guido Plotz
- Biomedical Research Laboratory, Department of Internal Medicine 1, Universitätsklinikum Frankfurt, Frankfurt, Germany
| | - Gabriel Capellá
- Hereditary Cancer Program, the Catalan Institute of Oncology (ICO), Hereditary Cancer Group, Molecular Mechanisms and Experimental Therapy in Oncology Program, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Ciber Oncología (CIBERONC) Instituto Salud Carlos III, L'Hospitalet de Llobregat, Barcelona, Spain.
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19
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Ben Sghaier R, Jansen AML, Bdioui A, Van Wezel T, Ksiaa M, Elgolli L, Ben Fatma L, Ben Ahmed S, Azzouz MM, Hellara O, Elghali A, Darbel F, Skandrani K, Mokkni M, Gdissa A, Ltaief R, Saad A, Hmila F, Gribaa M, Morreau H. Targeted next generation sequencing screening of Lynch syndrome in Tunisian population. Fam Cancer 2019; 18:343-348. [PMID: 31114938 DOI: 10.1007/s10689-019-00130-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
A high colorectal cancer (CRC) incidence is observed in Tunisia, with a relatively high proportion of patients developing CRC before the age of 40. While this suggests a genetic susceptibility, only a few Tunisian Lynch Syndrome families have been described. In this study we aimed to identify the underlying genetic cause in 32 patients with early onset CRC and/or a positive family history. Of twenty-four patients' tumor or biopsies could be analyzed with immunohistochemical staining to detect loss of expression of one of the MMR proteins. Ten tumors showed loss of expression, of which one tumor was from a patient where a germline pathogenic MSH2 variant was detected previously with Sanger sequencing. Next generation sequencing of the MMR, POLE and POLD1 genes was performed in leukocyte and tumor DNA of the remaining nine patients, as well as in two patients with MMR-proficient tumors, but with severe family history. In six of 11 patients a germline variant was detected in MLH1 (n = 5) or MSH2 (n = 1). Two of six patients were from the same family and both were found to carry a novel in-frame MLH1 deletion, predicted to affect MLH1 function. All MLH1 variant carriers had loss of heterozygosity with retention of the variant in the tumors, while a somatic pathogenic variant was detected in the patient with the germline MSH2 variant.
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Affiliation(s)
- Rihab Ben Sghaier
- Cytogenetic, Molecular Genetics and Human Reproduction Biology - Farhat, HACHED Hospital, Sousse, Tunisia.
| | | | - Ahlem Bdioui
- Cytology and Anatomopathology Department, Farhat HACHED Hospital, Sousse, Tunisia
| | - Tom Van Wezel
- Pathology Department, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
| | - Mehdi Ksiaa
- Gastroenterology Department, Sahloul Hospital, Sousse, Tunisia
| | | | - Leila Ben Fatma
- Carcinology Department, Farhat HACHED Hospital, Sousse, Tunisia
| | - Slim Ben Ahmed
- Carcinology Department, Farhat HACHED Hospital, Sousse, Tunisia
| | | | - Olfa Hellara
- Gastroenterology Department, Fatouma Bourguiba Hospital, Monastir, Tunisia
| | - Amine Elghali
- General Surgery Department, Farhat HACHED Hospital, Sousse, Tunisia
| | | | | | - Moncef Mokkni
- Cytology and Anatomopathology Department, Farhat HACHED Hospital, Sousse, Tunisia
| | - Ameni Gdissa
- Cytogenetic, Molecular Genetics and Human Reproduction Biology - Farhat, HACHED Hospital, Sousse, Tunisia
| | - Rached Ltaief
- General Surgery Department, Farhat HACHED Hospital, Sousse, Tunisia
| | - Ali Saad
- Cytogenetic, Molecular Genetics and Human Reproduction Biology - Farhat, HACHED Hospital, Sousse, Tunisia
| | - Fahmi Hmila
- General Surgery Department, Farhat HACHED Hospital, Sousse, Tunisia
| | - Moez Gribaa
- Cytogenetic, Molecular Genetics and Human Reproduction Biology - Farhat, HACHED Hospital, Sousse, Tunisia
| | - Hans Morreau
- Pathology Department, Leiden University Medical Centre (LUMC), Leiden, The Netherlands
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20
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Abildgaard AB, Stein A, Nielsen SV, Schultz-Knudsen K, Papaleo E, Shrikhande A, Hoffmann ER, Bernstein I, Gerdes AM, Takahashi M, Ishioka C, Lindorff-Larsen K, Hartmann-Petersen R. Computational and cellular studies reveal structural destabilization and degradation of MLH1 variants in Lynch syndrome. eLife 2019; 8:e49138. [PMID: 31697235 PMCID: PMC6837844 DOI: 10.7554/elife.49138] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 10/23/2019] [Indexed: 12/13/2022] Open
Abstract
Defective mismatch repair leads to increased mutation rates, and germline loss-of-function variants in the repair component MLH1 cause the hereditary cancer predisposition disorder known as Lynch syndrome. Early diagnosis is important, but complicated by many variants being of unknown significance. Here we show that a majority of the disease-linked MLH1 variants we studied are present at reduced cellular levels. We show that destabilized MLH1 variants are targeted for chaperone-assisted proteasomal degradation, resulting also in degradation of co-factors PMS1 and PMS2. In silico saturation mutagenesis and computational predictions of thermodynamic stability of MLH1 missense variants revealed a correlation between structural destabilization, reduced steady-state levels and loss-of-function. Thus, we suggest that loss of stability and cellular degradation is an important mechanism underlying many MLH1 variants in Lynch syndrome. Combined with analyses of conservation, the thermodynamic stability predictions separate disease-linked from benign MLH1 variants, and therefore hold potential for Lynch syndrome diagnostics.
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Affiliation(s)
- Amanda B Abildgaard
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
| | - Amelie Stein
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
| | - Sofie V Nielsen
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
| | - Katrine Schultz-Knudsen
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
| | - Elena Papaleo
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
| | - Amruta Shrikhande
- DNRF Center for Chromosome Stability, Department of Cellular and Molecular MedicineUniversity of CopenhagenCopenhagenDenmark
| | - Eva R Hoffmann
- DNRF Center for Chromosome Stability, Department of Cellular and Molecular MedicineUniversity of CopenhagenCopenhagenDenmark
| | - Inge Bernstein
- Department of Surgical GastroenterologyAalborg University HospitalAalborgDenmark
| | | | - Masanobu Takahashi
- Department of Medical OncologyTohoku University Hospital, Tohoku UniversitySendaiJapan
| | - Chikashi Ishioka
- Department of Medical OncologyTohoku University Hospital, Tohoku UniversitySendaiJapan
| | - Kresten Lindorff-Larsen
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
| | - Rasmus Hartmann-Petersen
- Department of Biology, The Linderstrøm-Lang Centre for Protein ScienceUniversity of CopenhagenCopenhagenDenmark
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21
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Conjunctival Melanoma: Genetic and Epigenetic Insights of a Distinct Type of Melanoma. Int J Mol Sci 2019; 20:ijms20215447. [PMID: 31683701 PMCID: PMC6862213 DOI: 10.3390/ijms20215447] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 10/25/2019] [Accepted: 10/28/2019] [Indexed: 12/19/2022] Open
Abstract
Conjunctival melanoma (CjM) is a rare, primary cancer of the ocular region. Genetic and epigenetic characteristics of conjunctival melanoma have not been completely elucidated yet. Conjunctival melanoma presents similarities with cutaneous melanoma, with substantial differences in the biological behavior. We reviewed the genetic and epigenetic insights of CjM involved in invasion and metastatic spread. CjM is commonly characterized by mutations of v-raf murine sarcoma viral oncogene homolog B1 (BRAF), neurofibromin 1 (NF1) and telomerase reverse transcriptase (TERT), high expression of mammalian target of rapamycin (mTOR) and heat shock protein 90 (HSP90), frequent phosphatase and tensin homolog (PTEN) loss and upregulation of specific miRNAs. These features should identify CjM as a distinct subset of melanoma with its own profile, which is more similar to cutaneous melanoma than mucosal melanoma and remarkably different from uveal melanoma.
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22
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Serra S, Capo-Chichi JM, McCarthy AJ, Sabatini P, Chetty R. Unique MLH1 mutations in colonic adenomas in an obligate germline Lynch syndrome carrier. J Clin Pathol 2019; 73:291-295. [PMID: 31649038 DOI: 10.1136/jclinpath-2019-206234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 10/05/2019] [Indexed: 11/03/2022]
Abstract
BACKGROUND An obligate germline Lynch syndrome carrier had four colonic adenomas removed. MATERIALS AND METHODS The adenomas were evaluated for grade of dysplasia, MLH1, PMS2, MSH2 and MSH6 protein expression, microsatellite instability (MSI), BRAF, methylation status and a next-generation sequencing (NGS) panel of 52 cancer genes. RESULTS There were four tubular or tubulovillous adenomas from the hepatic flexure, rectosigmoid and rectum; one with low-grade and high-grade dysplasia, one with high-grade dysplasia only and two with low-grade dysplasia. All four adenomas showed retention of MLH1, MHS2 and MSH6 but complete loss of PMS2 in both low-grade and high-grade dysplasia areas.Two of the four adenomas were MSI-high, BRAF V600E wild type and were not MLH1 methylated. NGS identified an MLH1 germline variant: NM_000249.3: c.1558+1 G>A, p.(?) in all tissue (adenomas and normal), which likely explains the pathophysiology of Lynch syndrome in this patient. Other variants were also detected in MLH1 and MSH6 in all four adenomas tested; these being reported previously in somatic colorectal cancers. CONCLUSION We highlight an MLH1 variant in the colonic adenomas in an obligate Lynch syndrome carrier that resulted in PMS2 protein loss in the absence of mutations of the PMS2 gene.
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Affiliation(s)
- Stefano Serra
- Laboratory Medicine Program, Divisions of Anatomical Pathology, University Health Network and University of Toronto, Toronto, Ontario, Canada
| | | | - Aoife J McCarthy
- Laboratory Medicine Program, Divisions of Anatomical Pathology, University Health Network and University of Toronto, Toronto, Ontario, Canada
| | - Peter Sabatini
- Clinical Laboratory Genetics, University Health Network, Toronto, Ontario, Canada
| | - Runjan Chetty
- Laboratory Medicine Program, Divisions of Anatomical Pathology, University Health Network and University of Toronto, Toronto, Ontario, Canada
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Lee SE, Lee HS, Kim KY, Park JH, Roh H, Park HY, Kim WS. High prevalence of the MLH1 V384D germline mutation in patients with HER2-positive luminal B breast cancer. Sci Rep 2019; 9:10966. [PMID: 31358837 PMCID: PMC6662670 DOI: 10.1038/s41598-019-47439-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 07/16/2019] [Indexed: 12/14/2022] Open
Abstract
HER2-positive luminal B breast cancer (BC), a subset of the luminal B subtype, is ER-positive and HER2-positive BC which is approximately 10% of all BC. However, HER2-positive luminal B BC has received less attention and is less represented in previous molecular analyses than other subtypes. Hence, it is important to elucidate the molecular biology of HER2-positive luminal B BC to stratify patients in a way that allows them to receive their respective optimal treatment. We performed molecular profiling using targeted next-generation sequencing on 94 HER2-positive luminal B BC to identify its molecular characteristics. A total of 134 somatic nonsynonymous mutations, including 131 nonsynonymous single nucleotide variants and three coding insertions/deletions were identified in 30 genes of 75 samples. PIK3CA was most frequently mutated (38/94, 40.4%), followed by TP53 (31/94, 33.0%), and others were detected at lower frequencies. Recurrent germline mutations of MLH1 V384D were found in 13.8% (13/94), with a significantly high TP53 mutations rate. The frequency of MLH1 V384D germline mutation in individuals with HER2-positive luminal B BC was significantly higher than that observed in the controls. All 13 cases were classified as microsatellite stable tumors. Tumor mutation burdens (TMB) were not significantly different between MLH1 V384D carrier and wild type. The concordant results of microsatellite instability (MSI) and TMB suggest that the haploinsufficiency of MLH1 plays a role as a tumor predisposition factor rather than a direct oncogenic driver. Our study identified, for the first time, that MLH1 V384D germline variant is frequently detected in HER2-positive luminal B BC. MLH1 V384D germline variant may not only contribute to gastrointestinal cancer predisposition but may also contribute to BC in East Asians.
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Affiliation(s)
- Seung Eun Lee
- Department of Pathology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea
| | - Hye Seung Lee
- Department of Pathology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea
| | | | - Jung-Hoon Park
- Precision Medicine Institute, Macrogen, Inc., Seoul, Korea
| | - Hanseong Roh
- Precision Medicine Institute, Macrogen, Inc., Seoul, Korea
| | - Ha Young Park
- Department of Pathology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
| | - Wan-Seop Kim
- Department of Pathology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea.
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24
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Samadder NJ, Giridhar KV, Baffy N, Riegert-Johnson D, Couch FJ. Hereditary Cancer Syndromes-A Primer on Diagnosis and Management: Part 1: Breast-Ovarian Cancer Syndromes. Mayo Clin Proc 2019; 94:1084-1098. [PMID: 31171119 DOI: 10.1016/j.mayocp.2019.02.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 02/05/2019] [Accepted: 02/14/2019] [Indexed: 12/12/2022]
Abstract
Cancer is the second leading cause of death in both men and women in the United States, with colorectal cancer and breast cancer being two of the most frequent cancer types. Hereditary causes occurring due to pathogenic sequence variants and defects in certain genes makes up roughly 5% of all colorectal cancers and breast-ovarian cancers. High-risk hereditary predisposition syndromes have been associated with a substantially increased lifetime risk for the development of colorectal cancers and breast-ovarian cancers depending on the genetic syndrome, and many people also carry an increased risk of several other cancers compared with the general population. The aim of this review was to provide comprehensive literature on the most commonly encountered hereditary predisposition syndromes, including Lynch syndrome, familial adenomatous polyposis, MUTYH-associated polyposis, hamartomatous polyposis, and breast-ovarian cancer conditions. This will be presented as a 2-part series: the first part will cover the breast-ovarian cancer syndromes, and the second will focus on the inherited colorectal cancer and polyposis conditions.
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Affiliation(s)
- N Jewel Samadder
- Division of Gastroenterology and Hepatology, Mayo Clinic, Scottsdale, AZ; Department of Clinical Genomics, Mayo Clinic, Scottsdale, AZ; Department of Clinical Genomics, Mayo Clinic, Jacksonville, FL.
| | | | - Noemi Baffy
- Division of Gastroenterology and Hepatology, Mayo Clinic, Scottsdale, AZ
| | - Douglas Riegert-Johnson
- Department of Clinical Genomics, Mayo Clinic, Scottsdale, AZ; Division of Gastroenterology and Hepatology, Mayo Clinic, Jacksonville, FL; Department of Clinical Genomics, Mayo Clinic, Jacksonville, FL
| | - Fergus J Couch
- Department of Laboratory Medicine, Mayo Clinic, Rochester, MN
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25
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Downs B, Sherman S, Cui J, Kim YC, Snyder C, Christensen M, Luo J, Lynch H, Wang SM. Common genetic variants contribute to incomplete penetrance: evidence from cancer-free BRCA1 mutation carriers. Eur J Cancer 2018; 107:68-78. [PMID: 30551077 DOI: 10.1016/j.ejca.2018.10.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Revised: 10/25/2018] [Accepted: 10/31/2018] [Indexed: 10/27/2022]
Abstract
PURPOSE The presence of pathogenic germline mutation in BRCA1 gene is considered as the most penetrant genetic predisposition for breast cancer. However, a portion of BRCA1 mutation carriers never develops breast cancer throughout their lifetime. This phenomenon is called incomplete penetrance. Genetic factor is proposed to contribute to this phenomenon, but the details regarding the genetic factor remain elusive. BRCA1 mutations were inherited from the ancestors of the mutation carrier families during human evolution, and their presence is a consistent threat to the survival of the mutation carrier population. In the present study, we hypothesize that evolution could positively select genetic components in the mutation carrier population to suppress the oncogenesis imposed by the predisposition. EXPERIMENTAL DESIGN To test our hypothesis, we used whole exome sequencing to compare germline variation of all genes in pairs of breast cancer-unaffected and breast cancer-affected BRCA1 mutation carriers, each pair was from the same family carrying the same BRCA1 mutation. RESULTS We identified a group of 'beneficial' variants enriched in the breast cancer-unaffected carrier group. These were the common variants in human population distributed in multiple genes involved in multiple functionally important pathways. We found a single-nucleotide polymorphism, rs3735400 located in ANLN gene, which plays an essential role in controlling cytokinesis and is often found to be overexpressed in cancer. The carriers of this variant had lower cumulative risk of developing breast cancer; overexpression of the variant-containing ANLN decreased ANLN nuclear localization suppressed expression of the variant-containing ANLN, and decreased the cellular proliferation respectively. CONCLUSION Our findings support our hypothesis that common genetic variants can be evolutionarily selected in BRCA1 mutation carrier population to counterpart the oncogenic effects imposed by mutation predisposition in BRCA1, contributing to the incomplete penetrance.
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Affiliation(s)
- Bradley Downs
- Department of Genetics, Cell Biology and Anatomy, College of Medicine, USA
| | - Simon Sherman
- Eppley Institute for Research in Cancer and Allied Diseases, USA
| | - Jian Cui
- Department of Genetics, Cell Biology and Anatomy, College of Medicine, USA
| | - Yeong C Kim
- Department of Genetics, Cell Biology and Anatomy, College of Medicine, USA
| | - Carrie Snyder
- Hereditary Cancer Center, Department of Preventive Medicine, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Maria Christensen
- Hereditary Cancer Center, Department of Preventive Medicine, Creighton University School of Medicine, Omaha, NE 68178, USA
| | - Jiangtao Luo
- Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Henry Lynch
- Hereditary Cancer Center, Department of Preventive Medicine, Creighton University School of Medicine, Omaha, NE 68178, USA.
| | - San Ming Wang
- Department of Genetics, Cell Biology and Anatomy, College of Medicine, USA; Cancer Centre and Institute of Translational Medicine, Faculty of Health Sciences, University of Macau, Taipa, Macau, SAR, China.
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26
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Weßbecher IM, Hinrichsen I, Funke S, Oellerich T, Plotz G, Zeuzem S, Grus FH, Biondi RM, Brieger A. DNA mismatch repair activity of MutLα is regulated by CK2-dependent phosphorylation of MLH1 (S477). Mol Carcinog 2018; 57:1723-1734. [DOI: 10.1002/mc.22892] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 06/22/2018] [Accepted: 08/18/2018] [Indexed: 12/15/2022]
Affiliation(s)
- Isabel M. Weßbecher
- Medical Clinic I; Biomedical Research Laboratory; Goethe-University; Frankfurt Germany
| | - Inga Hinrichsen
- Medical Clinic I; Biomedical Research Laboratory; Goethe-University; Frankfurt Germany
| | - Sebastian Funke
- Department of Ophthalmology; Experimental Ophthalmology; University Medical Center; Gutenberg University; Mainz Germany
| | - Thomas Oellerich
- Department of Medicine II, Hematology/Oncology; Goethe-University; Frankfurt Germany
| | - Guido Plotz
- Medical Clinic I; Biomedical Research Laboratory; Goethe-University; Frankfurt Germany
| | - Stefan Zeuzem
- Medical Clinic I; Biomedical Research Laboratory; Goethe-University; Frankfurt Germany
| | - Franz H. Grus
- Department of Ophthalmology; Experimental Ophthalmology; University Medical Center; Gutenberg University; Mainz Germany
| | - Ricardo M. Biondi
- Medical Clinic I; Biomedical Research Laboratory; Goethe-University; Frankfurt Germany
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET-Partner Institute of the Max Planck Society; Buenos Aires Argentina
| | - Angela Brieger
- Medical Clinic I; Biomedical Research Laboratory; Goethe-University; Frankfurt Germany
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27
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Shirts BH, Konnick EQ, Upham S, Walsh T, Ranola JMO, Jacobson AL, King MC, Pearlman R, Hampel H, Pritchard CC. Using Somatic Mutations from Tumors to Classify Variants in Mismatch Repair Genes. Am J Hum Genet 2018; 103:19-29. [PMID: 29887214 DOI: 10.1016/j.ajhg.2018.05.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/01/2018] [Indexed: 01/28/2023] Open
Abstract
Present guidelines for classification of constitutional variants do not incorporate inferences from mutations seen in tumors, even when these are associated with a specific molecular phenotype. When somatic mutations and constitutional mutations lead to the same molecular phenotype, as for the mismatch repair genes, information from somatic mutations may enable interpretation of previously unclassified variants. To test this idea, we first estimated likelihoods that somatic variants in MLH1, MSH2, MSH6, and PMS2 drive microsatellite instability and characteristic IHC staining patterns by calculating likelihoods of high versus low normalized variant read fractions of 153 mutations known to be pathogenic versus those of 760 intronic passenger mutations from 174 paired tumor-normal samples. Mutations that explained the tumor mismatch repair phenotype had likelihood ratio for high variant read fraction of 1.56 (95% CI 1.42-1.71) at sites with no loss of heterozygosity and of 26.5 (95% CI 13.2-53.0) at sites with loss of heterozygosity. Next, we applied these ratios to 165 missense, synonymous, and splice variants observed in tumors, combining in a Bayesian analysis the likelihood ratio corresponding with the adjusted variant read fraction with pretest probabilities derived from published analyses and public databases. We suggest classifications for 86 of 165 variants: 7 benign, 31 likely benign, 22 likely pathogenic, and 26 pathogenic. These results illustrate that for mismatch repair genes, characterization of tumor mutations permits tumor mutation data to inform constitutional variant classification. We suggest modifications to incorporate molecular phenotype in future variant classification guidelines.
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Affiliation(s)
- Brian H Shirts
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA.
| | - Eric Q Konnick
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
| | - Sarah Upham
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
| | - Tom Walsh
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | | | - Angela L Jacobson
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
| | - Mary-Claire King
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Rachel Pearlman
- Department of Internal Medicine, Division of Human Genetics, The Ohio State University Comprehensive Cancer Center, Columbus, OH 43221, USA
| | - Heather Hampel
- Department of Internal Medicine, Division of Human Genetics, The Ohio State University Comprehensive Cancer Center, Columbus, OH 43221, USA
| | - Colin C Pritchard
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
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28
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Jia P, Chai W. The MLH1 ATPase domain is needed for suppressing aberrant formation of interstitial telomeric sequences. DNA Repair (Amst) 2018; 65:20-25. [PMID: 29544212 DOI: 10.1016/j.dnarep.2018.03.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/02/2018] [Accepted: 03/05/2018] [Indexed: 02/05/2023]
Abstract
Genome instability gives rise to cancer. MLH1, commonly known for its important role in mismatch repair (MMR), DNA damage signaling and double-strand break (DSB) repair, safeguards genome stability. Recently we have reported a novel role of MLH1 in preventing aberrant formation of interstitial telomeric sequences (ITSs) at intra-chromosomal regions. Deficiency in MLH1, in particular its N-terminus, leads to an increase of ITSs. Here, we identify that the ATPase activity in the MLH1 N-terminal domain is important for suppressing the formation of ITSs. The ATPase activity is also needed for recruiting MLH1 to DSBs. Moreover, defective ATPase activity of MLH1 causes an increase in micronuclei formation. Our results highlight the crucial role of MLH1's ATPase domain in preventing the aberrant formation of telomeric sequences at the intra-chromosomal regions and preserving genome stability.
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Affiliation(s)
- Pingping Jia
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, United States
| | - Weihang Chai
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, United States.
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29
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Miyashita K, Fujii K, Suehiro Y, Taguchi K, Uike N, Yoshida MA, Oda S. Heterochronous occurrence of microsatellite instability in multiple myeloma - an implication for a role of defective DNA mismatch repair in myelomagenesis. Leuk Lymphoma 2018; 59:2454-2459. [PMID: 29384409 DOI: 10.1080/10428194.2018.1427862] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Kaname Miyashita
- a Department of Hematology , National Kyushu Cancer Center , Fukuoka , Japan.,b Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences , Kyushu University , Fukuoka , Japan
| | - Kei Fujii
- c Department of Surgery and Oncology, Graduate School of Medical Sciences , Kyushu University , Fukuoka , Japan
| | - Youko Suehiro
- a Department of Hematology , National Kyushu Cancer Center , Fukuoka , Japan
| | - Kenichi Taguchi
- d Clinical Research Institute, Cancer Genetics Laboratory , National Kyushu Cancer Center , Fukuoka , Japan
| | - Naokuni Uike
- a Department of Hematology , National Kyushu Cancer Center , Fukuoka , Japan
| | - Mitsuaki A Yoshida
- e Department of Radiation Biology, Institute of Radiation Emergency Medicine , Hirosaki University , Aomori , Japan
| | - Shinya Oda
- d Clinical Research Institute, Cancer Genetics Laboratory , National Kyushu Cancer Center , Fukuoka , Japan
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30
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Natarajan P, Gold NB, Bick AG, McLaughlin H, Kraft P, Rehm HL, Peloso GM, Wilson JG, Correa A, Seidman JG, Seidman CE, Kathiresan S, Green RC. Aggregate penetrance of genomic variants for actionable disorders in European and African Americans. Sci Transl Med 2017; 8:364ra151. [PMID: 27831900 DOI: 10.1126/scitranslmed.aag2367] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 09/30/2016] [Indexed: 12/21/2022]
Abstract
In populations that have not been selected for family history of disease, it is unclear how commonly pathogenic variants (PVs) in disease-associated genes for rare Mendelian conditions are found and how often they are associated with clinical features of these conditions. We conducted independent, prospective analyses of participants in two community-based epidemiological studies to test the hypothesis that persons carrying PVs in any of 56 genes that lead to 24 dominantly inherited, actionable conditions are more likely to exhibit the clinical features of the corresponding diseases than those without PVs. Among 462 European American Framingham Heart Study (FHS) and 3223 African-American Jackson Heart Study (JHS) participants who were exome-sequenced, we identified and classified 642 and 4429 unique variants, respectively, in these 56 genes while blinded to clinical data. In the same participants, we ascertained related clinical features from the participants' clinical history of cancer and most recent echocardiograms, electrocardiograms, and lipid measurements, without knowledge of variant classification. PVs were found in 5 FHS (1.1%) and 31 JHS (1.0%) participants. Carriers of PVs were more likely than expected, on the basis of incidence in noncarriers, to have related clinical features in both FHS (80.0% versus 12.4%) and JHS (26.9% versus 5.4%), yielding standardized incidence ratios of 6.4 [95% confidence interval (CI), 1.7 to 16.5; P = 7 × 10-4) in FHS and 4.7 (95% CI, 1.9 to 9.7; P = 3 × 10-4) in JHS. Individuals unselected for family history who carry PVs in 56 genes for actionable conditions have an increased aggregated risk of developing clinical features associated with the corresponding diseases.
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Affiliation(s)
- Pradeep Natarajan
- Center for Human Genetic Research, Cardiovascular Research Center, and Cardiology Division, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Nina B Gold
- Harvard Medical School, Boston, MA 02115, USA.,Boston Children's Hospital, Boston, MA 02115, USA
| | - Alexander G Bick
- Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Heather McLaughlin
- Harvard Medical School, Boston, MA 02115, USA.,Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA.,Partners HealthCare Personalized Medicine, Boston, MA 02115, USA
| | - Peter Kraft
- Departments of Epidemiology and Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Heidi L Rehm
- Harvard Medical School, Boston, MA 02115, USA.,Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA.,Partners HealthCare Personalized Medicine, Boston, MA 02115, USA
| | - Gina M Peloso
- Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - James G Wilson
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Adolfo Correa
- Departments of Pediatrics and Medicine, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Jonathan G Seidman
- Harvard Medical School, Boston, MA 02115, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Christine E Seidman
- Harvard Medical School, Boston, MA 02115, USA.,Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.,Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA.,Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Sekar Kathiresan
- Center for Human Genetic Research, Cardiovascular Research Center, and Cardiology Division, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA.,Harvard Medical School, Boston, MA 02115, USA.,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Robert C Green
- Harvard Medical School, Boston, MA 02115, USA. .,Broad Institute of Harvard and Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Partners HealthCare Personalized Medicine, Boston, MA 02115, USA.,Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA
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31
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Evaluation of reported pathogenic variants and their frequencies in a Japanese population based on a whole-genome reference panel of 2049 individuals. J Hum Genet 2017; 63:213-230. [PMID: 29192238 DOI: 10.1038/s10038-017-0347-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 08/25/2017] [Accepted: 08/29/2017] [Indexed: 01/07/2023]
Abstract
Clarifying allele frequencies of disease-related genetic variants in a population is important in genomic medicine; however, such data is not yet available for the Japanese population. To estimate frequencies of actionable pathogenic variants in the Japanese population, we examined the reported pathological variants in genes recommended by the American College of Medical Genetics and Genomics (ACMG) in our reference panel of genomic variations, 2KJPN, which was created by whole-genome sequencing of 2049 individuals of the resident cohort of the Tohoku Medical Megabank Project. We searched for pathogenic variants in 2KJPN for 57 autosomal ACMG-recommended genes responsible for 26 diseases and then examined their frequencies. By referring to public databases of pathogenic variations, we identified 143 reported pathogenic variants in 2KJPN for the 57 ACMG recommended genes based on a classification system. At the individual level, 21% of the individuals were found to have at least one reported pathogenic allele. We then conducted a literature survey to review the variants and to check for evidence of pathogenicity. Our results suggest that a substantial number of people have reported pathogenic alleles for the ACMG genes, and reviewing variants is indispensable for constructing the information infrastructure of genomic medicine for the Japanese population.
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32
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Sunga AY, Ricker C, Espenschied CR, Castillo D, Melas M, Herzog J, Bannon S, Cruz-Correa M, Lynch P, Solomon I, Gruber SB, Weitzel JN. Spectrum of mismatch repair gene mutations and clinical presentation of Hispanic individuals with Lynch syndrome. Cancer Genet 2017; 212-213:1-7. [PMID: 28449805 PMCID: PMC8800930 DOI: 10.1016/j.cancergen.2017.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 01/13/2017] [Accepted: 01/15/2017] [Indexed: 12/21/2022]
Abstract
Lynch syndrome (LS), the most common hereditary colorectal cancer syndrome, is caused by mismatch repair (MMR) gene mutations. However, data about MMR mutations in Hispanics are limited. This study aims to describe the spectrum of MMR mutations in Hispanics with LS and explore ancestral origins. This case series involved an IRB-approved retrospective chart review of self-identified Hispanic patients (n = 397) seen for genetic cancer risk assessment at four collaborating academic institutions in California, Texas, and Puerto Rico who were evaluated by MMR genotyping and/or tumor analysis. A literature review was conducted for all mutations identified. Of those who underwent clinical genetic testing (n = 176), 71 had MMR gene mutations. Nine mutations were observed more than once. One third (3/9) of recurrent mutations and two additional mutations (seen only once) were previously reported in Spain, confirming the influence of Spanish ancestry on MMR mutations in Hispanic populations. The recurrent mutations identified (n = 9) included both previously reported mutations as well as unique mutations not in the literature. This is the largest report of Hispanic MMR mutations in North America; however, a larger sample and haplotype analyses are needed to better understand recurrent MMR mutations in Hispanic populations.
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Affiliation(s)
- Annette Y Sunga
- Clinical Cancer Genetics, City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Charité Ricker
- USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
| | - Carin R Espenschied
- Clinical Cancer Genetics, City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Danielle Castillo
- Clinical Cancer Genetics, City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Marilena Melas
- USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
| | - Josef Herzog
- Clinical Cancer Genetics, City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Sarah Bannon
- Clinical Cancer Genetics, MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Marcia Cruz-Correa
- Clinical Cancer Genetics, University of Puerto Rico Comprehensive Cancer Center, Rio Piedras 00935, Puerto Rico
| | - Patrick Lynch
- Clinical Cancer Genetics, MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Ilana Solomon
- Clinical Cancer Genetics, City of Hope National Medical Center, Duarte, CA 91010, USA
| | - Stephen B Gruber
- USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90089, USA
| | - Jeffrey N Weitzel
- Clinical Cancer Genetics, City of Hope National Medical Center, Duarte, CA 91010, USA.
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33
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Ivanov M, Laktionov K, Breder V, Chernenko P, Novikova E, Telysheva E, Musienko S, Baranova A, Mileyko V. Towards standardization of next-generation sequencing of FFPE samples for clinical oncology: intrinsic obstacles and possible solutions. J Transl Med 2017; 15:22. [PMID: 28137276 PMCID: PMC5282851 DOI: 10.1186/s12967-017-1125-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 01/19/2017] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Next generation sequencing has a potential to revolutionize the management of cancer patients within the framework of precision oncology. Nevertheless, lack of standardization decelerated entering of the technology into the clinical testing space. Here we dissected a number of common problems of NGS diagnostics in oncology and introduced ways they can be resolved. METHODS DNA was extracted from 26 formalin fixed paraffin embedded (FFPE) specimens and processed with the TrueSeq Amplicon Cancer Panel (Illumina Inc, San Diego, California) targeting 48 cancer-related genes and sequenced in single run. Sequencing data were comparatively analyzed by several bioinformatics pipelines. RESULTS Libraries yielded sufficient coverage to detect even low prevalent mutations. We found that the number of FFPE sequence artifacts significantly correlates with pre-normalization concentration of libraries (rank correlation -0.81; p < 1e-10), thus, contributing to sample-specific variant detection cut-offs. Surprisingly, extensive validation of EGFR mutation calls by a combination of aligners and variant callers resulted in identification of two false negatives and one false positive that were due to complexity of underlying genomic change, confirmed by Sanger sequencing. Additionally, the study of the non-EGFR amplicons revealed 33 confirmed unique mutations in 17 genes, with TP53 being the most frequently mutated. Clinical relevance of these finding is discussed. CONCLUSIONS Reporting of entire mutational spectrum revealed by targeted sequencing is questionable, at least until the clinically-driven guidelines on reporting of somatic mutations are established. The standardization of sequencing protocols, especially their data analysis components, requires assay-, disease-, and, in many cases, even sample-specific customization that could be performed only in cooperation with clinicians.
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Affiliation(s)
- Maxim Ivanov
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Region, 141700 Russia
- Atlas Biomed Group, Moscow, 121069 Russia
- Institute of Chemical Biology and Fundamental Medicine of SB RAS, Novosibirsk, 630090 Russia
| | - Konstantin Laktionov
- N.N. Blokhin Russian Cancer Research Center, Ministry of Health of the Russian Federation, Kashirskoe sh. 24, Moscow, 115478 Russia
| | - Valery Breder
- N.N. Blokhin Russian Cancer Research Center, Ministry of Health of the Russian Federation, Kashirskoe sh. 24, Moscow, 115478 Russia
| | - Polina Chernenko
- N.N. Blokhin Russian Cancer Research Center, Ministry of Health of the Russian Federation, Kashirskoe sh. 24, Moscow, 115478 Russia
| | - Ekaterina Novikova
- Federal State Budgetary Institution Russian Scientific Center of Roentgenoradiology (RSCRR) of the Ministry of Healthcare of the Russian Federation (Russian Scientific Center of Roentgenoradiology), Moscow, 117485 Russia
| | - Ekaterina Telysheva
- Federal State Budgetary Institution Russian Scientific Center of Roentgenoradiology (RSCRR) of the Ministry of Healthcare of the Russian Federation (Russian Scientific Center of Roentgenoradiology), Moscow, 117485 Russia
| | | | - Ancha Baranova
- Moscow Institute of Physics and Technology (State University), Dolgoprudny, Moscow Region, 141700 Russia
- Atlas Biomed Group, Moscow, 121069 Russia
- Research Centre for Medical Genetics, Moscow, 115478 Russia
- Center for the Study of Chronic Metabolic and Rare Diseases, School of System Biology, George Mason University, Fairfax, VA USA
| | - Vladislav Mileyko
- Atlas Biomed Group, Moscow, 121069 Russia
- Institute of Chemical Biology and Fundamental Medicine of SB RAS, Novosibirsk, 630090 Russia
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Genetic Analysis of Mismatch Repair Genes Alterations in Extramammary Paget Disease. Am J Surg Pathol 2016; 40:1517-1525. [DOI: 10.1097/pas.0000000000000709] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Tricarico R, Kasela M, Mareni C, Thompson BA, Drouet A, Staderini L, Gorelli G, Crucianelli F, Ingrosso V, Kantelinen J, Papi L, De Angioletti M, Berardi M, Gaildrat P, Soukarieh O, Turchetti D, Martins A, Spurdle AB, Nyström M, Genuardi M. Assessment of the InSiGHT Interpretation Criteria for the Clinical Classification of 24 MLH1 and MSH2 Gene Variants. Hum Mutat 2016; 38:64-77. [PMID: 27629256 DOI: 10.1002/humu.23117] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 09/04/2016] [Accepted: 09/09/2016] [Indexed: 01/15/2023]
Abstract
Pathogenicity assessment of DNA variants in disease genes to explain their clinical consequences is an integral component of diagnostic molecular testing. The International Society for Gastrointestinal Hereditary Tumors (InSiGHT) has developed specific criteria for the interpretation of mismatch repair (MMR) gene variants. Here, we performed a systematic investigation of 24 MLH1 and MSH2 variants. The assessments were done by analyzing population frequency, segregation, tumor molecular characteristics, RNA effects, protein expression levels, and in vitro MMR activity. Classifications were confirmed for 15 variants and changed for three, and for the first time determined for six novel variants. Overall, based on our results, we propose the introduction of some refinements to the InSiGHT classification rules. The proposed changes have the advantage of homogenizing the InSIGHT interpretation criteria with those set out by the Evidence-based Network for the Interpretation of Germline Mutant Alleles (ENIGMA) consortium for the BRCA1/BRCA2 genes. We also observed that the addition of only few clinical data was sufficient to obtain a more stable classification for variants considered as "likely pathogenic" or "likely nonpathogenic." This shows the importance of obtaining as many as possible points of evidence for variant interpretation, especially from the clinical setting.
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Affiliation(s)
- Rossella Tricarico
- Department of Biomedical, Experimental and Clinical Sciences, Medical Genetics Unit, University of Florence, Florence, Italy.,Cancer Epigenetics and Cancer Biology Programs, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Mariann Kasela
- Department of Biosciences, Division of Genetics, University of Helsinki, Helsinki, Finland
| | | | - Bryony A Thompson
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah.,Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Victoria, Australia
| | - Aurélie Drouet
- Inserm-U1079-IRIB, Normandy Centre for Genomic and Personalized Medicine, University of Rouen, Rouen, France
| | - Lucia Staderini
- Department of Biomedical, Experimental and Clinical Sciences, Medical Genetics Unit, University of Florence, Florence, Italy.,Microbiology and Virology Department, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
| | - Greta Gorelli
- Department of Biomedical, Experimental and Clinical Sciences, Medical Genetics Unit, University of Florence, Florence, Italy
| | - Francesca Crucianelli
- Department of Biomedical, Experimental and Clinical Sciences, Medical Genetics Unit, University of Florence, Florence, Italy
| | - Valentina Ingrosso
- Department of Biomedical, Experimental and Clinical Sciences, Medical Genetics Unit, University of Florence, Florence, Italy
| | - Jukka Kantelinen
- Department of Biosciences, Division of Genetics, University of Helsinki, Helsinki, Finland
| | - Laura Papi
- Department of Biomedical, Experimental and Clinical Sciences, Medical Genetics Unit, University of Florence, Florence, Italy
| | - Maria De Angioletti
- Cancer Genetics and Gene Transfer - Core Research Laboratory, Istituto Toscano Tumori, Florence, Italy.,ICCOM-CNR, Sesto Fiorentino, Italy
| | - Margherita Berardi
- Cancer Genetics and Gene Transfer - Core Research Laboratory, Istituto Toscano Tumori, Florence, Italy
| | - Pascaline Gaildrat
- Inserm-U1079-IRIB, Normandy Centre for Genomic and Personalized Medicine, University of Rouen, Rouen, France
| | - Omar Soukarieh
- Inserm-U1079-IRIB, Normandy Centre for Genomic and Personalized Medicine, University of Rouen, Rouen, France
| | - Daniela Turchetti
- Medical Genetics, Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy
| | - Alexandra Martins
- Inserm-U1079-IRIB, Normandy Centre for Genomic and Personalized Medicine, University of Rouen, Rouen, France
| | - Amanda B Spurdle
- Genetics and Computational Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Minna Nyström
- Department of Biosciences, Division of Genetics, University of Helsinki, Helsinki, Finland
| | - Maurizio Genuardi
- Department of Biomedical, Experimental and Clinical Sciences, Medical Genetics Unit, University of Florence, Florence, Italy.,Institute of Genomic Medicine, A. Gemelli School of Medicine, Medical Genetics Unit, Catholic University of the Sacred Heart, Rome, Italy
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Chiu CH, Ho HL, Doong H, Yeh YC, Chen MY, Chou TY, Tsai CM. MLH1 V384D polymorphism associates with poor response to EGFR tyrosine kinase inhibitors in patients with EGFR L858R-positive lung adenocarcinoma. Oncotarget 2016; 6:8407-17. [PMID: 25823662 PMCID: PMC4480762 DOI: 10.18632/oncotarget.3511] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 02/02/2015] [Indexed: 01/13/2023] Open
Abstract
A significant fraction of patients with lung adenocarcinomas harboring activating epidermal growth factor receptor (EGFR) mutations do not experience clinical benefits from EGFR tyrosine kinase inhibitor (TKI) therapy. Using next-generation sequencing, we screened 739 mutation hotspots in 46 cancer-related genes in EGFR L858R-mutant lung adenocarcinomas from 29 patients who received EGFR-TKI therapy; 13 had short (< 3 months) and 16 had long (> 1 year) progression-free survival (PFS). We discovered MLH1 V384D as a genetic variant enriched in the group of patients with short PFS. Next, we investigated this genetic variation in 158 lung adenocarcinomas with the EGFR L858R mutation and found 14 (8.9%) patients had MLH1 V384D; available blood or non-tumor tissues from patients were also tested positive for MLH1 V384D. Patients with MLH1 V384D had a significantly shorter median PFS than those without (5.1 vs. 10.6 months; P= 0.001). Multivariate analysis showed that MLH1 V384D polymorphism was an independent predictor for a reduced PFS time (hazard ratio, 3.5; 95% confidence interval, 1.7 to 7.2; P= 0.001). In conclusion, MLH1 V384D polymorphism is associated with primary resistance to EGFR-TKIs in patients with EGFR L858R-positive lung adenocarcinoma and may potentially be a novel biomarker to guide treatment decisions.
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Affiliation(s)
- Chao-Hua Chiu
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan.,Department of Medicine, National Yang-Ming University, Taipei, Taiwan.,Division of Thoracic Oncology, Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Hsiang-Ling Ho
- Division of Molecular Pathology, Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Howard Doong
- Taipei VGH-Lihpao Laboratory of Cancer Genomic Medicine, Lihpao Life Science Corporation, Taipei, Taiwan
| | - Yi-Chen Yeh
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan.,Division of Molecular Pathology, Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Mei-Yu Chen
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan
| | - Teh-Ying Chou
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan.,Division of Molecular Pathology, Department of Pathology and Laboratory Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chun-Ming Tsai
- Department of Medicine, National Yang-Ming University, Taipei, Taiwan.,Division of Thoracic Oncology, Department of Chest Medicine, Taipei Veterans General Hospital, Taipei, Taiwan
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Novel Mutations in MLH1 and MSH2 Genes in Mexican Patients with Lynch Syndrome. Gastroenterol Res Pract 2016; 2016:5278024. [PMID: 27247567 PMCID: PMC4877485 DOI: 10.1155/2016/5278024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 04/14/2016] [Indexed: 12/23/2022] Open
Abstract
Background. Lynch Syndrome (LS) is characterized by germline mutations in the DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6, and PMS2. This syndrome is inherited in an autosomal dominant pattern and is characterized by early onset colorectal cancer (CRC) and extracolonic tumors. The aim of this study was to identify mutations in MMR genes in three Mexican patients with LS. Methods. Immunohistochemical analysis was performed as a prescreening method to identify absent protein expression. PCR, Denaturing High Performance Liquid Chromatography (dHPLC), and Sanger sequencing complemented the analysis. Results. Two samples showed the absence of nuclear staining for MLH1 and one sample showed loss of nuclear staining for MSH2. The mutations found in MLH1 gene were c.2103+1G>C in intron 18 and compound heterozygous mutants c.1852_1854delAAG (p.K618del) and c.1852_1853delinsGC (p.K618A) in exon 16. In the MSH2 gene, we identified mutation c.638dupT (p.L213fs) in exon 3. Conclusions. This is the first report of mutations in MMR genes in Mexican patients with LS and these appear to be novel.
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Lee AH, Fidock DA. Evidence of a Mild Mutator Phenotype in Cambodian Plasmodium falciparum Malaria Parasites. PLoS One 2016; 11:e0154166. [PMID: 27100094 PMCID: PMC4839739 DOI: 10.1371/journal.pone.0154166] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 04/09/2016] [Indexed: 12/22/2022] Open
Abstract
Malaria control efforts have been continuously stymied by drug-resistant strains of Plasmodium falciparum, which typically originate in Southeast Asia prior to spreading into high-transmission settings in Africa. One earlier proposed explanation for Southeast Asia being a hotbed of resistance has been the hypermutability or "Accelerated Resistance to Multiple Drugs" (ARMD) phenotype, whereby multidrug-resistant Southeast Asian parasites were reported to exhibit 1,000-fold higher rates of resistance to unrelated antimalarial agents when compared to drug-sensitive parasites. However, three recent studies do not recapitulate this hypermutability phenotype. Intriguingly, genome sequencing of recently derived multidrug-resistant Cambodian isolates has identified a high proportion of DNA repair gene mutations in multidrug-resistant parasites, suggesting their potential role in shaping local parasite evolution. By adapting fluctuation assays for use in P. falciparum, we have examined the in vitro mutation rates of five recent Cambodian isolates and three reference laboratory strains. For these studies we also generated a knockout parasite line lacking the DNA repair factor Exonuclease I. In these assays, parasites were typed for their ability to acquire resistance to KAE609, currently in advanced clinical trials, yielding 13 novel mutations in the Na+/H+-ATPase PfATP4, the primary resistance determinant. We observed no evidence of hypermutability. Instead, we found evidence of a mild mutator (up to a 3.4-fold increase in mutation rate) phenotype in two artemisinin-resistant Cambodian isolates, which carry DNA repair gene mutations. We observed that one such mutation in the Mismatch Repair protein Mlh1 contributes to the mild mutator phenotype when modeled in yeast (scmlh1-P157S). Compared to basal rates of mutation, a mild mutator phenotype may provide a greater overall benefit for parasites in Southeast Asia in terms of generating drug resistance without incurring detrimental fitness costs.
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Affiliation(s)
- Andrew H. Lee
- Department of Microbiology and Immunology, Columbia University, New York, New York, United States of America
| | - David A. Fidock
- Department of Microbiology and Immunology, Columbia University, New York, New York, United States of America
- Division of Infectious Diseases, Department of Medicine, Columbia University, New York, New York, United States of America
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Komine K, Shimodaira H, Takao M, Soeda H, Zhang X, Takahashi M, Ishioka C. Functional Complementation Assay for 47 MUTYH Variants in a MutY-Disrupted Escherichia coli Strain. Hum Mutat 2016; 36:704-11. [PMID: 25820570 PMCID: PMC4682456 DOI: 10.1002/humu.22794] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 03/25/2015] [Indexed: 12/27/2022]
Abstract
MUTYH-associated polyposis (MAP) is an adenomatous polyposis transmitted in an autosomal-recessive pattern, involving biallelic inactivation of the MUTYH gene. Loss of a functional MUTYH protein will result in the accumulation of G:T mismatched DNA caused by oxidative damage. Although p.Y179C and p.G396D are the two most prevalent MUTYH variants, more than 200 missense variants have been detected. It is difficult to determine whether these variants are disease-causing mutations or single-nucleotide polymorphisms. To understand the functional consequences of these variants, we generated 47 MUTYH gene variants via site-directed mutagenesis, expressed the encoded proteins in MutY-disrupted Escherichia coli, and assessed their abilities to complement the functional deficiency in the E. coli by monitoring spontaneous mutation rates. Although the majority of variants exhibited intermediate complementation relative to the wild type, some variants severely interfered with this complementation. However, some variants retained functioning similar to the wild type. In silico predictions of functional effects demonstrated a good correlation. Structural prediction of MUTYH based on the MutY protein structure allowed us to interpret effects on the protein stability or catalytic activity. These data will be useful for evaluating the functional consequences of missense MUTYH variants detected in patients with suspected MAP.
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Affiliation(s)
- Keigo Komine
- Department of Clinical Oncology, Institute of Development, Aging and Cancer, Tohoku University, Aoba-ku, Sendai, Japan.,Department of Clinical Oncology, Tohoku University Hospital, Aoba-ku, Sendai, Japan
| | - Hideki Shimodaira
- Department of Clinical Oncology, Institute of Development, Aging and Cancer, Tohoku University, Aoba-ku, Sendai, Japan.,Department of Clinical Oncology, Tohoku University Hospital, Aoba-ku, Sendai, Japan
| | - Masashi Takao
- Department of Molecular Genetics, Institute of Development, Aging and Cancer, Tohoku University, Aoba-ku, Sendai, Japan
| | - Hiroshi Soeda
- Department of Clinical Oncology, Institute of Development, Aging and Cancer, Tohoku University, Aoba-ku, Sendai, Japan.,Department of Clinical Oncology, Tohoku University Hospital, Aoba-ku, Sendai, Japan
| | - Xiaofei Zhang
- Department of Clinical Oncology, Institute of Development, Aging and Cancer, Tohoku University, Aoba-ku, Sendai, Japan
| | - Masanobu Takahashi
- Department of Clinical Oncology, Institute of Development, Aging and Cancer, Tohoku University, Aoba-ku, Sendai, Japan.,Department of Clinical Oncology, Tohoku University Hospital, Aoba-ku, Sendai, Japan
| | - Chikashi Ishioka
- Department of Clinical Oncology, Institute of Development, Aging and Cancer, Tohoku University, Aoba-ku, Sendai, Japan.,Department of Clinical Oncology, Tohoku University Hospital, Aoba-ku, Sendai, Japan
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40
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Hsieh YC, Cho EC, Tu SH, Wu CH, Hung CS, Hsieh MC, Su CT, Liu YR, Lee CH, Ho YS, Chiou HY. MSH2 rs2303425 Polymorphism is Associated with Early-Onset Breast Cancer in Taiwan. Ann Surg Oncol 2016; 24:603-610. [DOI: 10.1245/s10434-016-5168-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Indexed: 11/18/2022]
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Peña-Diaz J, Rasmussen LJ. Approaches to diagnose DNA mismatch repair gene defects in cancer. DNA Repair (Amst) 2015; 38:147-154. [PMID: 26708048 DOI: 10.1016/j.dnarep.2015.11.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 08/12/2015] [Accepted: 11/30/2015] [Indexed: 12/12/2022]
Abstract
The DNA repair pathway mismatch repair (MMR) is responsible for the recognition and correction of DNA biosynthetic errors caused by inaccurate nucleotide incorporation during replication. Faulty MMR leads to failure to address the mispairs or insertion deletion loops (IDLs) left behind by the replicative polymerases and results in increased mutation load at the genome. The realization that defective MMR leads to a hypermutation phenotype and increased risk of tumorigenesis highlights the relevance of this pathway for human disease. The association of MMR defects with increased risk of cancer development was first observed in colorectal cancer patients that carried inactivating germline mutations in MMR genes and the disease was named as hereditary non-polyposis colorectal cancer (HNPCC). Currently, a growing list of cancers is found to be MMR defective and HNPCC has been renamed Lynch syndrome (LS) partly to include the associated risk of developing extra-colonic cancers. In addition, a number of non-hereditary, mostly epigenetic, alterations of MMR genes have been described in sporadic tumors. Besides conferring a strong cancer predisposition, genetic or epigenetic inactivation of MMR genes also renders cells resistant to some chemotherapeutic agents. Therefore, diagnosis of MMR deficiency has important implications for the management of the patients, the surveillance of their relatives in the case of LS and for the choice of treatment. Some of the alterations found in MMR genes have already been well defined and their pathogenicity assessed. Despite this substantial wealth of knowledge, the effects of a large number of alterations remain uncharacterized (variants of uncertain significance, VUSs). The advent of personalized genomics is likely to increase the list of VUSs found in MMR genes and anticipates the need of diagnostic tools for rapid assessment of their pathogenicity. This review describes current tools and future strategies for addressing the relevance of MMR gene alterations in human disease.
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Affiliation(s)
- Javier Peña-Diaz
- Center for Healthy Aging, Department of Neuroscience and Pharmacology, University of Copenhagen, DK-2200 Copenhagen, Denmark.
| | - Lene Juel Rasmussen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, DK-2200 Copenhagen, Denmark.
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A founder MLH1 mutation in Lynch syndrome families from Piedmont, Italy, is associated with an increased risk of pancreatic tumours and diverse immunohistochemical patterns. Fam Cancer 2015; 13:401-13. [PMID: 24802709 DOI: 10.1007/s10689-014-9726-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The MLH1 c.2252_2253delAA mutation was found in 11 unrelated families from a restricted area south-west of Turin among 140 families with mutations in the mismatch repair genes. The mutation is located in the highly conserved C-terminal region, responsible for dimerization with the PMS2 protein. Twenty-five tumour tissues from 61 individuals with the c.2252_2253delAA mutation were tested for microsatellite instability (MSI) and protein expression. We compared the clinical features of these families versus the rest of our cohort and screened for a founder effect. All but one tumours showed the MSI-high mutator phenotype. Normal, focal and lack of MLH1 staining were observed in 16, 36 and 48 % of tumours, respectively. PMS2 expression was always lost. The mutation co-segregated with Lynch syndrome-related cancers in all informative families. All families but one fulfilled Amsterdam criteria, a frequency higher than in other MLH1 mutants. This was even more evident for AC II (72.7 vs. 57.5 %). Moreover, all families had at least one colon cancer diagnosed before 50 years and one case with multiple Lynch syndrome-related tumours. Interestingly, a statistically significant (p = 0.0057) higher frequency of pancreatic tumours was observed compared to families with other MLH1 mutations: 8.2 % of affected individuals versus 1.6 %. Haplotype analysis demonstrated a common ancestral origin of the mutation, which originated about 1,550 years ago. The mutation is currently classified as having an uncertain clinical significance. Clinical features, tissue analysis and co-segregation with disease strongly support the hypothesis that the MLH1 c.2252_2253delAA mutation has a pathogenic effect.
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Rossi D, Bruscaggin A, La Cava P, Galimberti S, Ciabatti E, Luminari S, Rigacci L, Tucci A, Pulsoni A, Bertoldero G, Vallisa D, Rusconi C, Spina M, Arcaini L, Angrilli F, Stelitano C, Merli F, Gaidano G, Federico M, Palumbo GA. The genotype of MLH1 identifies a subgroup of follicular lymphoma patients who do not benefit from doxorubicin: FIL-FOLL study. Haematologica 2015; 100:517-24. [PMID: 25596266 DOI: 10.3324/haematol.2014.108183] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Though most follicular lymphoma biomarkers rely on tumor features, the host genetic background may also be relevant for outcome. Here we aimed at verifying the contribution of candidate polymorphisms of FCγ receptor, DNA repair and detoxification genes to prognostic stratification of follicular lymphoma treated with immunochemotherapy. The study was based on 428 patients enrolled in the FOLL05 prospective trial that compared three standard-of-care regimens (rituximab-cyclophosphamide-vincristine-prednisone versus rituximab-cyclophosphamide-doxorubicin-vincristine-prednisone versus rituximab-fludarabine-mitoxantrone) for the first line therapy of advanced follicular lymphoma. Polymorphisms were genotyped on peripheral blood DNA samples. The primary endpoint was time to treatment failure. Polymorphisms of FCGR2A and FCGR3A, which have been suggested to influence the activity of rituximab as a single agent, did not affect time to treatment failure in the pooled analysis of the three FOLL05 treatment arms that combined rituximab with chemotherapy (P=0.742, P=0.252, respectively). These results were consistent even when the analysis was conducted by intention to treat, indicating that different chemotherapy regimens and loads did not interact differentially with the FCGR2A and FCGR3A genotypes. The genotype of MLH1, which regulates the genotoxic effect of doxorubicin, significantly affected time to treatment failure in patients in the rituximab-cyclophosphamide-doxorubicin-vincristine-prednisone arm (P=0.001; q<0.1), but not in arms in which patients did not receive doxorubicin (i.e., the rituximab-cyclophosphamide-vincristine-prednisone and rituximab-fludarabine-mitoxantrone arms). The impact of MLH1 on time to treatment failure was independent after adjusting for the Follicular Lymphoma International Prognostic Index and other potential confounding variables by multivariate analysis. These data indicate that MLH1 genotype is a predictor of failure to benefit from rituximab-cyclophosphamide-doxorubicin-vincristine-prednisone treatment in advanced follicular lymphoma and confirm that FCGR2A and FCGR3A polymorphisms have no impact when follicular lymphoma is treated with rituximab plus chemotherapy (clinicaltrials.gov identifier: NCT00774826).
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Affiliation(s)
- Davide Rossi
- Division of Hematology, Department of Translational Medicine, Amedeo Avogadro University of Eastern Piedmont, Novara
| | - Alessio Bruscaggin
- Division of Hematology, Department of Translational Medicine, Amedeo Avogadro University of Eastern Piedmont, Novara
| | - Piera La Cava
- Division of Hematology, AOU "Policlinico V. Emanuele", Catania
| | - Sara Galimberti
- Department of Oncology, Transplants and Advanced Technologies, Section of Haematology, University of Pisa
| | - Elena Ciabatti
- Department of Oncology, Transplants and Advanced Technologies, Section of Haematology, University of Pisa
| | - Stefano Luminari
- Department of Oncology and Hematology, University of Modena and Reggio Emilia, Modena
| | - Luigi Rigacci
- Division of Hematology, Azienda Ospedaliero Universitaria Careggi, Florence
| | - Alessandra Tucci
- Division of Hematology, Spedali Civili Hospital and University, Brescia
| | - Alessandro Pulsoni
- Hematology, Department of Cellular Biotechnologies and Hematology, Sapienza University, Rome
| | | | | | - Chiara Rusconi
- Division of Hematology, Department of Hematology and Oncology, Niguarda Hospital, Milan
| | - Michele Spina
- Division of Medical Oncology A, National Cancer Institute, Aviano
| | - Luca Arcaini
- Divisions of Hematology, Fondazione IRCCS Policlinico San Matteo, University of Pavia
| | | | | | - Francesco Merli
- Hematology Unit, Arcispedale Santa Maria Nuova, Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia, Italy
| | - Gianluca Gaidano
- Division of Hematology, Department of Translational Medicine, Amedeo Avogadro University of Eastern Piedmont, Novara
| | - Massimo Federico
- Department of Oncology and Hematology, University of Modena and Reggio Emilia, Modena
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Hinrichsen I, Schäfer D, Langer D, Köger N, Wittmann M, Aretz S, Steinke V, Holzapfel S, Trojan J, König R, Zeuzem S, Brieger A, Plotz G. Functional testing strategy for coding genetic variants of unclear significance in MLH1 in Lynch syndrome diagnosis. Carcinogenesis 2014; 36:202-11. [PMID: 25477341 DOI: 10.1093/carcin/bgu239] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Lynch syndrome is caused by inactivating mutations in the MLH1 gene, but genetic variants of unclear significance frequently preclude diagnosis. Functional testing can reveal variant-conferred defects in gene or protein function. Based on functional defect frequencies and clinical applicability of test systems, we developed a functional testing strategy aimed at efficiently detecting pathogenic defects in coding MLH1 variants. In this strategy, tests of repair activity and expression are prioritized over analyses of subcellular protein localization and messenger RNA (mRNA) formation. This strategy was used for four unclear coding MLH1 variants (p.Asp41His, p.Leu507Phe, p.Gln689Arg, p.Glu605del + p.Val716Met). Expression was analyzed using a transfection system, mismatch repair (MMR) activity by complementation in vitro, mRNA formation by reverse transcriptase-PCR in carrier lymphocyte mRNA, and subcellular localization with dye-labeled fusion constructs. All tests included clinically meaningful controls. The strategy enabled efficient identification of defects in two unclear variants: the p.Asp41His variant showed loss of MMR activity, whereas the compound variant p.Glu605del + p.Val716Met had a defect of expression. This expression defect was significantly stronger than the pathogenic expression reference variant analyzed in parallel, therefore the defect of the compound variant is also pathogenic. Interestingly, the expression defect was caused additively by both of the compound variants, at least one of which is non-pathogenic when occurring by itself. Tests were neutral for p.Leu507Phe and p.Gln689Arg, and the results were consistent with available clinical data. We finally discuss the improved sensitivity and efficiency of the applied strategy and its limitations in analyzing unclear coding MLH1 variants.
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Affiliation(s)
- Inga Hinrichsen
- Biomedical Research Laboratory, Department of Internal Medicine 1 and Department of Human Genetics, Universitätsklinikum Frankfurt, Frankfurt D-60590, Germany, Institute of Human Genetics, University of Bonn, Bonn D-53127, Germany and Department of Internal Medicine 1, Universitätsklinikum Frankfurt D-60590, Frankfurt, Germany
| | - Dieter Schäfer
- Department of Human Genetics, Universitätsklinikum Frankfurt, Frankfurt D-60590, Germany
| | - Deborah Langer
- Biomedical Research Laboratory, Department of Internal Medicine 1 and Department of Human Genetics, Universitätsklinikum Frankfurt, Frankfurt D-60590, Germany, Institute of Human Genetics, University of Bonn, Bonn D-53127, Germany and Department of Internal Medicine 1, Universitätsklinikum Frankfurt D-60590, Frankfurt, Germany
| | - Nicole Köger
- Biomedical Research Laboratory, Department of Internal Medicine 1 and Department of Human Genetics, Universitätsklinikum Frankfurt, Frankfurt D-60590, Germany, Institute of Human Genetics, University of Bonn, Bonn D-53127, Germany and Department of Internal Medicine 1, Universitätsklinikum Frankfurt D-60590, Frankfurt, Germany
| | - Margarethe Wittmann
- Biomedical Research Laboratory, Department of Internal Medicine 1 and Department of Human Genetics, Universitätsklinikum Frankfurt, Frankfurt D-60590, Germany, Institute of Human Genetics, University of Bonn, Bonn D-53127, Germany and Department of Internal Medicine 1, Universitätsklinikum Frankfurt D-60590, Frankfurt, Germany
| | - Stefan Aretz
- Institute of Human Genetics, University of Bonn, Bonn D-53127, Germany and
| | - Verena Steinke
- Institute of Human Genetics, University of Bonn, Bonn D-53127, Germany and
| | - Stefanie Holzapfel
- Institute of Human Genetics, University of Bonn, Bonn D-53127, Germany and
| | - Jörg Trojan
- Department of Internal Medicine 1, Universitätsklinikum Frankfurt D-60590, Frankfurt, Germany
| | - Rainer König
- Department of Human Genetics, Universitätsklinikum Frankfurt, Frankfurt D-60590, Germany
| | - Stefan Zeuzem
- Department of Internal Medicine 1, Universitätsklinikum Frankfurt D-60590, Frankfurt, Germany
| | - Angela Brieger
- Biomedical Research Laboratory, Department of Internal Medicine 1 and Department of Human Genetics, Universitätsklinikum Frankfurt, Frankfurt D-60590, Germany, Institute of Human Genetics, University of Bonn, Bonn D-53127, Germany and Department of Internal Medicine 1, Universitätsklinikum Frankfurt D-60590, Frankfurt, Germany
| | - Guido Plotz
- Biomedical Research Laboratory, Department of Internal Medicine 1 and Department of Human Genetics, Universitätsklinikum Frankfurt, Frankfurt D-60590, Germany, Institute of Human Genetics, University of Bonn, Bonn D-53127, Germany and Department of Internal Medicine 1, Universitätsklinikum Frankfurt D-60590, Frankfurt, Germany
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45
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Challenges in assessing pathogenicity based on frequency of variants in mismatch repair genes: an extreme case of a MSH2 variant and a meta-analysis. Gene 2014; 546:421-4. [PMID: 24933000 DOI: 10.1016/j.gene.2014.06.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 04/30/2014] [Accepted: 06/13/2014] [Indexed: 11/21/2022]
Abstract
The clinical interpretation of variants in mismatch repair (MMR) genes associated with Lynch syndrome can be confusing when the functional nature of the variant is not clearly defined. We report an extreme case where a polymorphism in the MSH2 gene which had a low minor allele frequency, was misclassified as a mutation based on low evidential methods in the database and previous publications. We expanded this experience to perform a systematic meta-analysis in order to investigate other variants that have potentially been misclassified. Our results suggested that the interpretation of pathogenicity should be more cautious and emphasized the need for solid validation through multiple analyses including functional analysis for variants in MMR genes.
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46
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Dominguez-Valentin M, Drost M, Therkildsen C, Rambech E, Ehrencrona H, Angleys M, Lau Hansen T, de Wind N, Nilbert M, Juel Rasmussen L. Functional implications of the p.Cys680Arg mutation in the MLH1 mismatch repair protein. Mol Genet Genomic Med 2014; 2:352-5. [PMID: 25077178 PMCID: PMC4113276 DOI: 10.1002/mgg3.80] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 02/26/2014] [Accepted: 02/28/2014] [Indexed: 12/15/2022] Open
Abstract
In clinical genetic diagnostics, it is difficult to predict whether genetic mutations that do not greatly alter the primary sequence of the encoded protein causing unknown functional effects on cognate proteins lead to development of disease. Here, we report the clinical identification of c.2038 T>C missense mutation in exon 18 of the human MLH1 gene and biochemically characterization of the p.Cys680Arg mutant MLH1 protein to implicate it in the pathogenicity of the Lynch syndrome (LS). We show that the mutation is deficient in DNA mismatch repair and, therefore, contributing to LS in the carriers.
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Affiliation(s)
- Mev Dominguez-Valentin
- Department of Oncology, Institute for Clinical Sciences, Lund University 22185, Lund, Sweden ; The Danish HNPCC-register, Clinical Research Centre, Hvidovre University Hospital, Copenhagen University Hvidovre, Denmark
| | - Mark Drost
- Department of Toxicogenetics, Leiden University Medical Center Leiden, The Netherlands
| | - Christina Therkildsen
- The Danish HNPCC-register, Clinical Research Centre, Hvidovre University Hospital, Copenhagen University Hvidovre, Denmark
| | - Eva Rambech
- Department of Oncology, Institute for Clinical Sciences, Lund University 22185, Lund, Sweden
| | - Hans Ehrencrona
- Department of Clinical Genetics, University and Regional Laboratories, Skåne University Hospital, Lund University Lund, Sweden
| | - Maria Angleys
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen DK-2200, Copenhagen N, Denmark
| | - Thomas Lau Hansen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen DK-2200, Copenhagen N, Denmark
| | - Niels de Wind
- Department of Toxicogenetics, Leiden University Medical Center Leiden, The Netherlands
| | - Mef Nilbert
- Department of Oncology, Institute for Clinical Sciences, Lund University 22185, Lund, Sweden ; The Danish HNPCC-register, Clinical Research Centre, Hvidovre University Hospital, Copenhagen University Hvidovre, Denmark
| | - Lene Juel Rasmussen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen DK-2200, Copenhagen N, Denmark
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47
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Abulí A, Bujanda L, Muñoz J, Buch S, Schafmayer C, Valeria Maiorana M, Veneroni S, van Wezel T, Liu T, Westers H, Esteban-Jurado C, Ocaña T, Piqué JM, Andreu M, Jover R, Carracedo A, Xicola RM, Llor X, Castells A, Dunlop M, Hofstra R, Lindblom A, Wijnen J, Peterlongo P, Hampe J, Ruiz-Ponte C, Castellví-Bel S. The MLH1 c.1852_1853delinsGC (p.K618A) variant in colorectal cancer: genetic association study in 18,723 individuals. PLoS One 2014; 9:e95022. [PMID: 24743384 PMCID: PMC3990597 DOI: 10.1371/journal.pone.0095022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 03/21/2014] [Indexed: 12/25/2022] Open
Abstract
Colorectal cancer is one of the most frequent neoplasms and an important cause of mortality in the developed world. Mendelian syndromes account for about 5% of the total burden of CRC, being Lynch syndrome and familial adenomatous polyposis the most common forms. Lynch syndrome tumors develop mainly as a consequence of defective DNA mismatch repair associated with germline mutations in MLH1, MSH2, MSH6 and PMS2. A significant proportion of variants identified by screening these genes correspond to missense or noncoding changes without a clear pathogenic consequence, and they are designated as “variants of uncertain significance”, being the c.1852_1853delinsGC (p.K618A) variant in the MLH1 gene a clear example. The implication of this variant as a low-penetrance risk variant for CRC was assessed in the present study by performing a case-control study within a large cohort from the COGENT consortium-COST Action BM1206 including 18,723 individuals (8,055 colorectal cancer cases and 10,668 controls) and a case-only genotype-phenotype correlation with several clinical and pathological characteristics restricted to the Epicolon cohort. Our results showed no involvement of this variant as a low-penetrance variant for colorectal cancer genetic susceptibility and no association with any clinical and pathological characteristics including family history for this neoplasm or Lynch syndrome.
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Affiliation(s)
- Anna Abulí
- Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain
- Department of Gastroenterology, Hospital del Mar-IMIM (Hospital del Mar Medical Research Centre), Pompeu Fabra University, Barcelona, Catalonia, Spain
| | - Luis Bujanda
- Gastroenterology Department, Hospital Donostia, Networked Biomedical Research Centre for Hepatic and Digestive Diseases (CIBEREHD), Basque Country University, San Sebastián, Spain
| | - Jenifer Muñoz
- Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain
| | - Stephan Buch
- Department of Medine I, University Hospital Dresden, Dresden, Germany
| | - Clemens Schafmayer
- Department of General and Thoracic Surgery, University Hospital Schleswig-Holstein, Kiel, Germany
| | | | - Silvia Veneroni
- Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Tom van Wezel
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
| | - Tao Liu
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | - Helga Westers
- Department of Genetics, University Medical Center Groningen, Groningen, The Netherlands
| | - Clara Esteban-Jurado
- Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain
| | - Teresa Ocaña
- Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain
| | - Josep M. Piqué
- Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain
| | - Montserrat Andreu
- Department of Gastroenterology, Hospital del Mar-IMIM (Hospital del Mar Medical Research Centre), Pompeu Fabra University, Barcelona, Catalonia, Spain
| | - Rodrigo Jover
- Department of Gastroenterology, Hospital General d'Alacant, Alicante, Spain
| | - Angel Carracedo
- Galician Public Foundation of Genomic Medicine (FPGMX), Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Genomics Medicine Group, Hospital Clínico, Santiago de Compostela, University of Santiago de Compostela, Galicia, Spain
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia
| | - Rosa M. Xicola
- Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Xavier Llor
- Section of Digestive Diseases and Nutrition, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Antoni Castells
- Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain
| | | | - Malcolm Dunlop
- Colon Cancer Genetics Group, Institute of Genetics and Molecular Medicine, University of Edinburgh and MRC Human Genetics Unit, Edinburgh, United Kingdom
| | - Robert Hofstra
- Department of Genetics, University Medical Center Groningen, Groningen, The Netherlands
| | - Annika Lindblom
- Department of Molecular Medicine and Surgery, Karolinska Institute, Stockholm, Sweden
| | - Juul Wijnen
- Departments of Human Genetics and Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Paolo Peterlongo
- IFOM, Fondazione Istituto FIRC di Oncologia Molecolare, Milan, Italy
| | - Jochen Hampe
- Department of Medine I, University Hospital Dresden, Dresden, Germany
| | - Clara Ruiz-Ponte
- Galician Public Foundation of Genomic Medicine (FPGMX), Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Genomics Medicine Group, Hospital Clínico, Santiago de Compostela, University of Santiago de Compostela, Galicia, Spain
| | - Sergi Castellví-Bel
- Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain
- * E-mail:
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48
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Martín-López JV, Fishel R. The mechanism of mismatch repair and the functional analysis of mismatch repair defects in Lynch syndrome. Fam Cancer 2014; 12:159-68. [PMID: 23572416 DOI: 10.1007/s10689-013-9635-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The majority of Lynch syndrome (LS), also known as hereditary non-polyposis colorectal cancer (HNPCC), has been linked to heterozygous defects in DNA mismatch repair (MMR). MMR is a highly conserved pathway that recognizes and repairs polymerase misincorporation errors and nucleotide damage as well as functioning as a damage sensor that signals apoptosis. Loss-of-heterozygosity (LOH) that retains the mutant MMR allele and epigenetic silencing of MMR genes are associated with an increased mutation rate that drives carcinogenesis as well as microsatellite instability that is a hallmark of LS/HNPCC. Understanding the biophysical functions of the MMR components is crucial to elucidating the role of MMR in human tumorigenesis and determining the pathogenetic consequences of patients that present in the clinic with an uncharacterized variant of the MMR genes. We summarize the historical association between LS/HNPCC and MMR, discuss the mechanism of the MMR and finally examine the functional analysis of MMR defects found in LS/HNPCC patients and their relationship with the severity of the disease.
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Affiliation(s)
- Juana V Martín-López
- Department of Molecular Virology, Immunology and Medical Genetics, Human Cancer Genetics, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA
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49
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Mensenkamp AR, Vogelaar IP, van Zelst-Stams WAG, Goossens M, Ouchene H, Hendriks-Cornelissen SJB, Kwint MP, Hoogerbrugge N, Nagtegaal ID, Ligtenberg MJL. Somatic mutations in MLH1 and MSH2 are a frequent cause of mismatch-repair deficiency in Lynch syndrome-like tumors. Gastroenterology 2014; 146:643-646.e8. [PMID: 24333619 DOI: 10.1053/j.gastro.2013.12.002] [Citation(s) in RCA: 263] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 11/27/2013] [Accepted: 12/05/2013] [Indexed: 01/03/2023]
Abstract
Lynch syndrome is caused by germline mutations in the mismatch repair (MMR) genes. Tumors are characterized by microsatellite instability (MSI). However, a considerable number of MSI-positive tumors have no known molecular mechanism of development. By using Sanger and ion semiconductor sequencing, 25 MSI-positive tumors were screened for somatic mutations and loss of heterozygosity in mutL homolog 1 (MLH1) and mutS homolog 2 (MSH2). In 13 of 25 tumors (8 MLH1-deficient and 5 MSH2-deficient tumors), we identified 2 somatic mutations in these genes. We conclude that 2 acquired events explain the MMR-deficiency in more than 50% of the MMR-deficient tumors without causal germline mutations or promoter methylation.
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Affiliation(s)
- Arjen R Mensenkamp
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands.
| | - Ingrid P Vogelaar
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands
| | | | - Monique Goossens
- Department of Pathology, Radboud university medical center, Nijmegen, The Netherlands
| | - Hicham Ouchene
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands
| | | | - Michael P Kwint
- Department of Pathology, Radboud university medical center, Nijmegen, The Netherlands
| | - Nicoline Hoogerbrugge
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands
| | - Iris D Nagtegaal
- Department of Pathology, Radboud university medical center, Nijmegen, The Netherlands
| | - Marjolijn J L Ligtenberg
- Department of Human Genetics, Radboud university medical center, Nijmegen, The Netherlands; Department of Pathology, Radboud university medical center, Nijmegen, The Netherlands
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50
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Thompson BA, Spurdle AB, Plazzer JP, Greenblatt MS, Akagi K, Al-Mulla F, Bapat B, Bernstein I, Capellá G, den Dunnen JT, du Sart D, Fabre A, Farrell MP, Farrington SM, Frayling IM, Frebourg T, Goldgar DE, Heinen CD, Holinski-Feder E, Kohonen-Corish M, Robinson KL, Leung SY, Martins A, Moller P, Morak M, Nystrom M, Peltomaki P, Pineda M, Qi M, Ramesar R, Rasmussen LJ, Royer-Pokora B, Scott RJ, Sijmons R, Tavtigian SV, Tops CM, Weber T, Wijnen J, Woods MO, Macrae F, Genuardi M. Application of a 5-tiered scheme for standardized classification of 2,360 unique mismatch repair gene variants in the InSiGHT locus-specific database. Nat Genet 2013; 46:107-115. [PMID: 24362816 DOI: 10.1038/ng.2854] [Citation(s) in RCA: 342] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 11/26/2013] [Indexed: 12/12/2022]
Abstract
The clinical classification of hereditary sequence variants identified in disease-related genes directly affects clinical management of patients and their relatives. The International Society for Gastrointestinal Hereditary Tumours (InSiGHT) undertook a collaborative effort to develop, test and apply a standardized classification scheme to constitutional variants in the Lynch syndrome-associated genes MLH1, MSH2, MSH6 and PMS2. Unpublished data submission was encouraged to assist in variant classification and was recognized through microattribution. The scheme was refined by multidisciplinary expert committee review of the clinical and functional data available for variants, applied to 2,360 sequence alterations, and disseminated online. Assessment using validated criteria altered classifications for 66% of 12,006 database entries. Clinical recommendations based on transparent evaluation are now possible for 1,370 variants that were not obviously protein truncating from nomenclature. This large-scale endeavor will facilitate the consistent management of families suspected to have Lynch syndrome and demonstrates the value of multidisciplinary collaboration in the curation and classification of variants in public locus-specific databases.
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Affiliation(s)
- Bryony A Thompson
- Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, Brisbane, Australia.,School of Medicine, University of Queensland, Brisbane, Australia
| | - Amanda B Spurdle
- Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - John-Paul Plazzer
- Department of Colorectal Medicine and Genetics, Royal Melbourne Hospital, Australia
| | - Marc S Greenblatt
- Vermont Cancer Center, University of Vermont College of Medicine, Burlington, VT, USA
| | - Kiwamu Akagi
- Division of Molecular Diagnosis and Cancer Prevention, Saitama Cancer Center, Saitama, Japan
| | - Fahd Al-Mulla
- Department of Pathology, Faculty of Medicine, Health Sciences Center, Kuwait University, Safat, Kuwait
| | - Bharati Bapat
- Department of Lab Medicine and Pathobiology, University of Toronto, Canada
| | - Inge Bernstein
- Danish HNPCC Registry, Copenhagen, Denmark.,Surgical Gastroenterology Department, Aalborg University Hospital, Aalborg, Denmark
| | - Gabriel Capellá
- Hereditary Cancer Program, Catalan Institute of Oncology-IDIBELL, Barcelona, Spain
| | - Johan T den Dunnen
- Center of Human and Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Desiree du Sart
- Molecular Genetics Lab, Victorian Clinical Genetics Services, Murdoch Childrens Research Institute, Melbourne, Australia
| | - Aurelie Fabre
- INSERM UMR S910, Department of Medical Genetics and Functional Genomics, Marseille, France
| | - Michael P Farrell
- Department of Cancer Genetics, Mater Private Hospital, Dublin, Ireland
| | - Susan M Farrington
- Colon Cancer Genetics Group, Institute of Genetics and Molecular Medicine, University of Edinburgh, Scotland
| | - Ian M Frayling
- Institute of Medical Genetics, University Hospital of Wales, Cardiff, UK
| | - Thierry Frebourg
- Inserm U1079, Faculty of Medicine, Institute for Biomedical Research, University of Rouen, France
| | - David E Goldgar
- Department of Dermatology, University of Utah Medical School, Salt Lake City, UT, USA.,Huntsman Cancer Institute, Salt Lake City, UT, USA
| | - Christopher D Heinen
- Center for Molecular Medicine, UConn Health Center, Farmington, CT, USA.,Neag Comprehensive Cancer Center, UConn Health Center, Farmington, CT, USA
| | - Elke Holinski-Feder
- MGZ - Medizinisch Genetisches Zentrum, Munich, Germany.,Klinikum der Universität München, Campus Innenstadt, Medizinische Klinik und Poliklinik IV, Munich, Germany
| | - Maija Kohonen-Corish
- School of Medicine, University of Western Sydney, Sydney, Australia.,The Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, Australia.,St Vincent's Clinical School, University of NSW, Sydney, Australia
| | - Kristina Lagerstedt Robinson
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Suet Yi Leung
- Hereditary Gastrointestinal Cancer Genetic Diagnosis Laboratory, Department of Pathology, The University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong
| | - Alexandra Martins
- Inserm U1079, University of Rouen, Institute for Research and Innovation in Biomedicine, Rouen, France
| | - Pal Moller
- Research Group on Inherited Cancer, Department of Medical Genetics, Oslo University Hospital, The Norwegian Radium Hospital, Oslo, Norway
| | - Monika Morak
- MGZ - Medizinisch Genetisches Zentrum, Munich, Germany.,Klinikum der Universität München, Campus Innenstadt, Medizinische Klinik und Poliklinik IV, Munich, Germany
| | - Minna Nystrom
- Division of Genetics, Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Paivi Peltomaki
- Department of Medical Genetics, Haartman Institute, University of Helsinki, Finland
| | - Marta Pineda
- Hereditary Cancer Program, Catalan Institute of Oncology-IDIBELL, Barcelona, Spain
| | - Ming Qi
- Center for Genetic and Genomic Medicine, The First Affiliated Hospital of Zhejiang University School of Medicine, James Watson Institute of Genomic Sciences, Beijing Genome Institute, China.,University of Rochester Medical Center, NY, USA
| | - Rajkumar Ramesar
- MRC Human Genetics Research Unit, Division of Human Genetics, Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, South Africa
| | | | | | - Rodney J Scott
- Discipline of Medical Genetics, Faculty of Health, University of Newcastle, The Hunter Medical Research Institute, NSW, Australia.,The Division of Molecular Medicine, Hunter Area Pathology Service, John Hunter Hospital, Newcastle, NSW, Australia
| | - Rolf Sijmons
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | | | - Carli M Tops
- Center of Human and Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Thomas Weber
- State University of New York at Downstate, Brooklyn, NY, USA
| | - Juul Wijnen
- Center of Human and Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Michael O Woods
- Discipline of Genetics, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Finlay Macrae
- Department of Colorectal Medicine and Genetics, Royal Melbourne Hospital, Australia
| | - Maurizio Genuardi
- Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Italy.,Fiorgen Foundation for Pharmacogenomics, Sesto Fiorentino, Italy
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