1
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Li CG, Jin P, Yang L, Zang WC, Kang Q, Li N, He Y, Xu J, Zhang C, Wang X, Sheng JQ. Germline mutations in patients with multiple colorectal polyps in China. J Gastroenterol Hepatol 2017; 32:1723-1729. [PMID: 28251689 DOI: 10.1111/jgh.13776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 01/12/2017] [Accepted: 02/24/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND AND AIM Multiple colorectal polyps are relevant in hereditary colorectal cancer (CRC) syndromes, which are thought to be caused by multiple events including germline mutations. This study was aimed to characterize germline mutations in Chinese patients with multiple colorectal polyps. METHODS Patients with > 10 colorectal polyps at the Department of Gastroenterology of the PLA Army General Hospital were enrolled from January 2014 to December 2015. These patients were divided into the high-risk, moderate-risk, and mild-risk groups. White blood cell samples were collected, and DNA was extracted to sequence a panel of 19 genes previously associated with CRC by next-generation sequencing. RESULTS A total of 96 patients were enrolled in the study. Pathogenic germline mutations were found in 24 (24/33, 72.73%), nine (9/24, 37.5%), and three patients (3/39, 7.7%) in the high-risk, moderate-risk, and mild-risk groups, respectively. Based on the results given, we suggested a strategy about gene sequencing test for the patients with multiple polyps, and the sensitivity and specificity of the screening strategy were 97% and 57%, respectively. Four of eight patients with MUTYH pathogenic germline mutations had the c.A934-2G monoallelic germline mutation, whereas three of eight patients had the C55T MUTYH germline mutation. Concurrent pathogenic germline mutations in APC and MUTYH were also observed. CONCLUSIONS A genetic screening strategy comprising 19 genes was effective to screen for hereditary CRC syndromes in patients with multiple colorectal polyps. The MUTYH germline mutation hotspots in Chinese patients may be different from those in Caucasian patients.
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Affiliation(s)
- Chen-Guang Li
- The Third Military Medical University, Chongqing, China.,Department of Gastroenterology, PLA Army General Hospital, Beijing, China
| | - Peng Jin
- Department of Gastroenterology, PLA Army General Hospital, Beijing, China
| | - Lang Yang
- Department of Gastroenterology, PLA Army General Hospital, Beijing, China
| | - Wan-Chun Zang
- Novogene Bioinformatics Technology Co., Ltd, Beijing, China
| | - Qian Kang
- Department of Gastroenterology, PLA Army General Hospital, Beijing, China
| | - Na Li
- Department of Gastroenterology, PLA Army General Hospital, Beijing, China
| | - Yuqi He
- Department of Gastroenterology, PLA Army General Hospital, Beijing, China
| | - Junfeng Xu
- Department of Gastroenterology, PLA Army General Hospital, Beijing, China
| | - Chen Zhang
- Department of Gastroenterology, PLA Army General Hospital, Beijing, China
| | - Xin Wang
- Department of Gastroenterology, PLA Army General Hospital, Beijing, China
| | - Jian-Qiu Sheng
- Department of Gastroenterology, PLA Army General Hospital, Beijing, China
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2
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First description of mutational analysis of MLH1, MSH2 and MSH6 in Algerian families with suspected Lynch syndrome. Fam Cancer 2017; 16:57-66. [PMID: 27468915 DOI: 10.1007/s10689-016-9917-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Hereditary non-polyposis colorectal cancer (HNPCC) is an autosomal dominant disorder characterized by the early onset of colorectal cancer (CRC) linked to germline defects in Mismatch Repair (MMR) genes. We present here, the first molecular study of the correlation between CRC and mutations occurring in these genes performed in twenty-one unrelated Algerian families. The presence of germline mutations in MMR genes, MLH1, MSH2 and MSH6 genes was tested by sequencing all exons plus adjacent intronic sequences and Multiplex ligand-dependent probe amplification (MLPA) for testing large genomic rearrangements. Pathogenic mutations were identified in 20 % of families with clinical suspicion on HNPCC. Two novel variants described for the first time in Algerian families were identified in MLH1, c.881_884delTCAGinsCATTCCT and a large deletion in MSH6 gene from a young onset of CRC. Moreover, the variants of MSH2 gene: c.942+3A>T, c.1030C>T, the most described ones, were also detected in Algerian families. Furthermore, the families HNPCC caused by MSH6 germline mutation may show an age of onset that is comparable to this of patients with MLH1 and MSH2 mutations. In this study, we confirmed that MSH2, MLH1, and MSH6 contribute to CRC susceptibility. This work represents the implementation of a diagnostic algorithm for the identification of Lynch syndrome patients in Algerian families.
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3
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Ye X, Deng H, Su M, Liao Q, Huang D, Liao DF, Xiao ZQ, Cao D. A complex microsatellite at chromosome 7q33 as a new prognostic marker of colorectal cancer. Oncotarget 2017; 8:88760-88769. [PMID: 29179473 PMCID: PMC5687643 DOI: 10.18632/oncotarget.21077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 06/28/2017] [Indexed: 11/25/2022] Open
Abstract
Disease-specific markers are critical for early diagnosis, targeted therapy and prognostic prediction of diseases. Current study reports a complex microsatellite as a new prognostic marker of sporadic colorectal cancer. This microsatellite located at Chromosome 7q33 is composed of three tetranucleotide tandem repeats, (TTCC)2(TCCC)5(TCCT)7, flanked by a CT-rich sequence. We analyzed polymorphisms of this microsatellite in 158 sporadic colorectal cancer, 143 matched normal adjacent tissues (NAT) and 150 health donors. Our results showed that this complex microsatellite was instable with polymorphic frequency of 77.2% in colorectal cancer, 52.4% in NAT and 54.7% in health donors (p<0.01) when compared to reference sequence. In the three tandem repeats, (TCCT)7 site was most polymorphic accounting for over 70.0% of polymorphisms in this complex microsatellite, followed by (TTCC)2 site for approximately 20%. Polymorphisms in (TCCC)5 was rare. Polymorphisms at the (TCCT)7 site were mainly insertions of 1 to 4 copies of TCCT (88.6%), and deletions occurred in about 6.4% of cases. The (TTCC)2 site was featured with one copy TTCC insertions. Pair-wise analyses between colorectal tumors and NAT revealed that 88 of 121 (72.7%) tumors displayed expansion, contraction or both in these tetranucleotide tandem repeats when compared to NAT. A cross-analysis with clinicopathological data of 158 colorectal cancers revealed that polymorphic alterations of the microsatellite associated with less lymphatic metastasis (p<0.001), and the colorectal cancer patients with polymorphic changes in this microsatellite demonstrated better survival (n=112, p=0.0058). Together these data suggest that this complex microsatellite is a potential prognostic marker of sporadic colorectal cancer.
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Affiliation(s)
- Xu Ye
- Research Center of Carcinogenesis and Targeted Therapy, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China.,The Higher Educational Key Laboratory For Cancer Proteomics and Translational Medicine of Hunan province, Xiangya Hospital, Central South University, Changsha, Hunan 410005, China.,Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China
| | - Hongyu Deng
- Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China
| | - Min Su
- Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China
| | - Qianjin Liao
- Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China
| | - Dan Huang
- Division of Stem Cell Regulation and Application, State Key Laboratory of Chinese Medicine Powder and Medicine Innovation in Hunan (incubation), Hunan University of Chinese Medicine, Changsha, Hunan 410208, China
| | - Duan-Fang Liao
- Division of Stem Cell Regulation and Application, State Key Laboratory of Chinese Medicine Powder and Medicine Innovation in Hunan (incubation), Hunan University of Chinese Medicine, Changsha, Hunan 410208, China
| | - Zhi-Qiang Xiao
- Research Center of Carcinogenesis and Targeted Therapy, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China.,The Higher Educational Key Laboratory For Cancer Proteomics and Translational Medicine of Hunan province, Xiangya Hospital, Central South University, Changsha, Hunan 410005, China
| | - Deliang Cao
- Hunan Cancer Hospital and The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, Hunan 410013, China.,Division of Stem Cell Regulation and Application, State Key Laboratory of Chinese Medicine Powder and Medicine Innovation in Hunan (incubation), Hunan University of Chinese Medicine, Changsha, Hunan 410208, China
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4
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Yokoo Y, Kijima A, Ishii Y, Takasu S, Tsuchiya T, Umemura T. Effects of Nrf2 silencing on oxidative stress-associated intestinal carcinogenesis in mice. Cancer Med 2016; 5:1228-38. [PMID: 26899729 PMCID: PMC4924381 DOI: 10.1002/cam4.672] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/23/2016] [Accepted: 01/25/2016] [Indexed: 12/22/2022] Open
Abstract
To assess the risk of colorectal cancer in humans with inactivation of NRF2, Nrf2‐proficient (Nrf2+/+) and ‐deficient (Nrf2−/−) mice were exposed to potassium bromate (KBrO3) at concentrations of 750 or 1500 ppm for 52 weeks. Neoplastic proliferative lesions were observed in the small intestine and exhibited accumulations of β‐catenin and cyclin D1. The lesions had characteristics similar to those in experimental models of human hereditary colorectal cancer. An additional 13‐week study was performed to examine the role of Nrf2 in the effects of oxidative stress. Significant increase in combined incidences of preneoplastic and neoplastic lesions in Nrf2−/− mice administered high‐dose KBrO3. In the short‐term study, although 8‐hydroxydeoxyguanosine (8‐OHdG) levels in the epithelial DNA of Nrf2−/− mice at the high dose were significantly lower than those of the corresponding Nrf2+/+ mice, the difference was very small. mRNA levels of Nrf2‐regulated genes were increased in Nrf2+/+ mice. Overexpression of cyclooxygenase 2 (COX2) and increased numbers of proliferating cell nuclear antigen (PCNA)‐positive cells in the jejunal crypts were observed in Nrf2−/− mice administered high‐dose KBrO3. Overall, these data suggested that individuals having single‐nucleotide polymorphisms in NRF2 may have a risk of colorectal cancer to some extent.
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Affiliation(s)
- Yuh Yokoo
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
| | - Aki Kijima
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
| | - Yuji Ishii
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
| | - Shinji Takasu
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
| | - Takuma Tsuchiya
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
| | - Takashi Umemura
- Division of Pathology, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo, 158-8501, Japan
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5
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Dhivya S, Premkumar K. Nomadic genetic elements contribute to oncogenic translocations: Implications in carcinogenesis. Crit Rev Oncol Hematol 2015; 98:81-93. [PMID: 26548742 DOI: 10.1016/j.critrevonc.2015.10.012] [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: 03/04/2015] [Revised: 10/05/2015] [Accepted: 10/27/2015] [Indexed: 12/22/2022] Open
Abstract
Chromosomal translocations as molecular signatures have been reported in various malignancies but, the mechanism behind which is largely unknown. Swapping of chromosomal fragments occurs by induction of double strand breaks (DSBs), most of which were initially assumed de novo. However, decoding of human genome proved that transposable elements (TE) might have profound influence on genome integrity. TEs are highly conserved mobile genetic elements that generate DSBs, subsequently resulting in large chromosomal rearrangements. Previously TE insertions were thought to be harmless, but recently gains attention due to the origin of spectrum of post-insertional genomic alterations and subsequent transcriptional alterations leading to development of deleterious effects mainly carcinogenesis. Though the existing knowledge on the cancer-associated TE dynamics is very primitive, exploration of underlying mechanism promises better therapeutic strategies for cancer. Thus, this review focuses on the prevalence of TE in the genome, associated genomic instability upon transposition activation and impact on tumorigenesis.
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Affiliation(s)
- Sridaran Dhivya
- Cancer Genetics and Nanomedicine Laboratory, Department of Biomedical Science, School of Basic Medical Sciences, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India
| | - Kumpati Premkumar
- Cancer Genetics and Nanomedicine Laboratory, Department of Biomedical Science, School of Basic Medical Sciences, Bharathidasan University, Tiruchirappalli 620 024, Tamil Nadu, India.
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6
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Bashyam MD, Kotapalli V, Raman R, Chaudhary AK, Yadav BK, Gowrishankar S, Uppin SG, Kongara R, Sastry RA, Vamsy M, Patnaik S, Rao S, Dsouza S, Desai D, Tester A. Evidence for presence of mismatch repair gene expression positive Lynch syndrome cases in India. Mol Carcinog 2014; 54:1807-14. [PMID: 25420488 DOI: 10.1002/mc.22244] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Accepted: 10/01/2014] [Indexed: 01/09/2023]
Abstract
Lynch syndrome (LS), the most common form of familial CRC predisposition that causes tumor onset at a young age, is characterized by the presence of microsatellite instability (MSI) in tumors due to germline inactivation of mismatch repair (MMR) system. Two MMR genes namely MLH1 and MSH2 account for majority of LS cases while MSH6 and PMS2 may account for a minor proportion. In order to identify MMR genes causing LS in India, we analyzed MSI and determined expression status of the four MMR genes in forty eight suspected LS patient colorectal tumor samples. Though a majority exhibited MSI, only 58% exhibited loss of MMR expression, a significantly low proportion compared to reports from other populations. PCR-DNA sequencing and MLPA-based mutation and exonic deletion/duplication screening respectively, revealed genetic lesions in samples with and without MMR gene expression. Interestingly, tumor samples with and without MMR expression exhibited significant differences with respect to histological (mucin content) and molecular (instability exhibited by mononucleotide microsatellites) features. The study has revealed for the first time a significant proportion of LS tumors not exhibiting loss of MMR expression.
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Affiliation(s)
- Murali D Bashyam
- Laboratory of Molecular Oncology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Viswakalyan Kotapalli
- Laboratory of Molecular Oncology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Ratheesh Raman
- Laboratory of Molecular Oncology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Ajay K Chaudhary
- Laboratory of Molecular Oncology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | - Brijesh K Yadav
- Laboratory of Molecular Oncology, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| | | | | | | | | | - Mohana Vamsy
- Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, India
| | - Sujit Patnaik
- Basavatarakam Indo-American Cancer Hospital and Research Institute, Hyderabad, India
| | - Satish Rao
- Krishna Institute of Medical Sciences, Hyderabad, India
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7
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Fusco F, Paciolla M, Napolitano F, Pescatore A, D'Addario I, Bal E, Lioi MB, Smahi A, Miano MG, Ursini MV. Genomic architecture at the Incontinentia Pigmenti locus favours de novo pathological alleles through different mechanisms. Hum Mol Genet 2011; 21:1260-71. [PMID: 22121116 DOI: 10.1093/hmg/ddr556] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
IKBKG/NEMO gene mutations cause an X-linked, dominant neuroectodermal disorder named Incontinentia Pigmenti (IP). Located at Xq28, IKBKG/NEMO has a unique genomic organization, as it is part of a segmental duplication or low copy repeat (LCR1-LCR2, >99% identical) containing the gene and its pseudogene copy (IKBKGP). In the opposite direction and outside LCR1, IKBKG/NEMO partially overlaps G6PD, whose mutations cause a common X-linked human enzymopathy. The two LCRs in the IKBKG/NEMO locus are able to recombine through non-allelic homologous recombination producing either a pathological recurrent exon 4-10 IKBKG/NEMO deletion (IKBKGdel) or benign small copy number variations. We here report that the local high frequency of micro/macro-homologies, tandem repeats and repeat/repetitive sequences make the IKBKG/NEMO locus susceptible to novel pathological IP alterations. Indeed, we describe the first two independent instances of inter-locus gene conversion, occurring between the two LCRs, that copies the IKBKGP pseudogene variants into the functional IKBKG/NEMO, causing the de novo occurrence of p.Glu390ArgfsX61 and the IKBKGdel mutations, respectively. Subsequently, by investigating a group of 20 molecularly unsolved IP subjects using a high-density quantitative polymerase chain reaction assay, we have identified seven unique de novo deletions varying from 4.8 to ∼115 kb in length. Each deletion removes partially or completely both IKBKG/NEMO and the overlapping G6PD, thereby uncovering the first deletions disrupting the G6PD gene which were found in patients with IP. Interestingly, the 4.8 kb deletion removes the conserved bidirectional promoterB, shared by the two overlapping IKBKG/NEMO and G6PD genes, leaving intact the alternative IKBKG/NEMO unidirectional promoterA. This promoter, although active in the keratinocytes of the basal dermal layer, is down-regulated during late differentiation. Genomic analysis at the breakpoint sites indicated that other mutational forces, such as non-homologous end joining, Alu-Alu-mediated recombination and replication-based events, might enhance the vulnerability of the IP locus to produce de novo pathological IP alleles.
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Affiliation(s)
- Francesca Fusco
- Institute of Genetics and Biophysics Adriano Buzzati-Traverso, IGB-CNR, Naples 80131, Italy
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8
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Pérez-Cabornero L, Infante Sanz M, Velasco Sampedro E, Lastra Aras E, Acedo Becares A, Miner Pino C, Durán Domínguez M. Frequency of rearrangements in Lynch syndrome cases associated with MSH2: characterization of a new deletion involving both EPCAM and the 5' part of MSH2. Cancer Prev Res (Phila) 2011; 4:1556-62. [PMID: 21791569 DOI: 10.1158/1940-6207.capr-11-0080] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Lynch syndrome is caused by germline mutations in MSH2, MLH1, MSH6, and PMS2 mismatch repair genes and leads to a high risk of colorectal and endometrial cancer. It was recently shown that constitutional 3' end deletions of EPCAM could cause Lynch syndrome in tissues with MSH2 deficiency. We aim to establish the spectrum of mutations in MSH2-associated Lynch syndrome cases and their clinical implications. Probands from 159 families suspected of having Lynch syndrome were enrolled in the study. Immunohistochemistry and microsatellite instability (MSI) analyses were used on the probands of all families. Eighteen cases with MSH2 loss were identified: eight had point mutations in MSH2. In 10 Lynch syndrome families without MSH2 mutations, EPCAM-MSH2genomic rearrangement screening was carried out with the use of multiplex ligation-dependent probe amplification and reverse transcriptase PCR. We report that large germline deletions, encompassing one or more exons of the MSH2 gene, cosegregate with the Lynch syndrome phenotype in 23% (8 of 35) of MSI families tested. A new combined deletion EPCAM-MSH2 was identified and characterized by break point analysis, encompassing from the 3' end region of EPCAM to the 5' initial sequences of the MSH2 (c.859-1860_MSH2:646-254del). EPCAM-MSH2 fusion transcript was isolated. The tumors of the carriers show high-level MSI and MSH2 protein loss. The clinical correlation provided evidence that the type of mutation and the extension of the deletions involving the MSH2 gene could have different implications in cancer predisposition. Thus, the identification of EPCAM-MSH2 rearrangements and their comprehensive characterization should be included in the routine mutation screening protocols for Lynch syndrome.
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Affiliation(s)
- Lucia Pérez-Cabornero
- Cancer Genetics Laboratory, Instituto de Biología y Genética Molecular, University of Valladolid, Spain
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9
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Komm M, Kronawitter-Fesl M, Kremer M, Lutz L, Holinski-Feder E, Kopp R. Primary mucinous adenocarcinoma of the vermiform appendix with high grade microsatellite instability. J Cancer 2011; 2:302-6. [PMID: 21716905 PMCID: PMC3119391 DOI: 10.7150/jca.2.302] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Accepted: 05/13/2011] [Indexed: 12/16/2022] Open
Abstract
Primary adenocarcinoma of the vermiform appendix is a rare entity and is frequently discovered by the pathologist following appendectomy for suspected appendicitis.We present a 42-year-old male with primary mucinous adenocarcinoma of the appendix initially presenting symptoms of acute appendicitis. Histological investigation of the appendectomy specimen showed a mucinous adenocarcinoma and the patient was treated by secondary right hemicolectomy giving the final histopathological classification of an UICC IIIC tumor. Since the patient fulfills the revised Bethesda criteria analysis of immunoreactivity of DNA mismatch repair proteins was performed showing loss of MLH1 and MSH2 expression associated with high microsatellite instability (MSI-H), not yet reported for primary mucinous appendiceal carcinoma. Further genetic analysis for DNA mismatch repair gene mutations were negative. The patient received intensified adjuvant chemotherapy according to the FOLFOX-4-scheme, since MSI-H colorectal carcinomas might show lower response rates following standard 5-FU-based adjuvant chemotherapy.
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Affiliation(s)
- Moritz Komm
- 1. Department of General Surgery, Klinikum München-Harlaching, Munich, Germany
| | | | - Marcus Kremer
- 2. Department of Pathology, Klinikum München-Harlaching, Munich, Germany
| | - Ludwig Lutz
- 3. Department of Haematology and Oncology, Klinikum München-Harlaching, Munich, Germany
| | | | - Reinhard Kopp
- 1. Department of General Surgery, Klinikum München-Harlaching, Munich, Germany
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10
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Konkel MK, Batzer MA. A mobile threat to genome stability: The impact of non-LTR retrotransposons upon the human genome. Semin Cancer Biol 2010; 20:211-21. [PMID: 20307669 DOI: 10.1016/j.semcancer.2010.03.001] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 03/04/2010] [Accepted: 03/16/2010] [Indexed: 02/06/2023]
Abstract
It is now commonly agreed that the human genome is not the stable entity originally presumed. Deletions, duplications, inversions, and insertions are common, and contribute significantly to genomic structural variations (SVs). Their collective impact generates much of the inter-individual genomic diversity observed among humans. Not only do these variations change the structure of the genome; they may also have functional implications, e.g. altered gene expression. Some SVs have been identified as the cause of genetic disorders, including cancer predisposition. Cancer cells are notorious for their genomic instability, and often show genomic rearrangements at the microscopic and submicroscopic level to which transposable elements (TEs) contribute. Here, we review the role of TEs in genome instability, with particular focus on non-LTR retrotransposons. Currently, three non-LTR retrotransposon families - long interspersed element 1 (L1), SVA (short interspersed element (SINE-R), variable number of tandem repeats (VNTR), and Alu), and Alu (a SINE) elements - mobilize in the human genome, and cause genomic instability through both insertion- and post-insertion-based mutagenesis. Due to the abundance and high sequence identity of TEs, they frequently mislead the homologous recombination repair pathway into non-allelic homologous recombination, causing deletions, duplications, and inversions. While less comprehensively studied, non-LTR retrotransposon insertions and TE-mediated rearrangements are probably more common in cancer cells than in healthy tissue. This may be at least partially attributed to the commonly seen global hypomethylation as well as general epigenetic dysfunction of cancer cells. Where possible, we provide examples that impact cancer predisposition and/or development.
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Affiliation(s)
- Miriam K Konkel
- Department of Biological Sciences, Biological Computation and Visualization Center, Louisiana State University, Baton Rouge, LA 70803, USA
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11
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A study on MSH2 and MLH1 mutations in hereditary nonpolyposis colorectal cancer families from the Basque Country, describing four new germline mutations. Fam Cancer 2010; 8:533-9. [PMID: 19760518 DOI: 10.1007/s10689-009-9283-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Hereditary non-polyposis colorectal cancer (HNPCC) or Lynch syndrome underlies between 2 and 5% of all colorectal cancer. It is inherited as an autosomal dominant condition due to mutations in the mismatch repair genes. Fifty-four non-related index cases, 21 of them fulfilling Amsterdam criteria I or II, were studied. Ten (10/21 = 47.6%) different pathological mutations were found in this group, two of which had not previously been reported--one in MLH1 and the other in MSH2-. In the remaining patients, we also found another family with one of these new mutations, and four additional changes, two of which were also new--a pathological change in MSH2 and a second change of uncertain significance in MLH1-, while the other two changes had already been reported. Of all mutations, eight were found in MSH2 (8/15 = 53.3%) and seven in MLH1 (7/15 = 46.6%), suggesting a slightly greater involvement of MSH2 in HNPCC than MLH1 in our population, in contrast to the results reported by other authors.
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12
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Zavodna K, Krivulcik T, Bujalkova MG, Slamka T, Martinicky D, Ilencikova D, Bartosova Z. Partial loss of heterozygosity events at the mutated gene in tumors from MLH1/MSH2 large genomic rearrangement carriers. BMC Cancer 2009; 9:405. [PMID: 19930554 PMCID: PMC2788582 DOI: 10.1186/1471-2407-9-405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 11/20/2009] [Indexed: 11/24/2022] Open
Abstract
Background Depending on the population studied, large genomic rearrangements (LGRs) of the mismatch repair (MMR) genes constitute various proportions of the germline mutations that predispose to hereditary non-polyposis colorectal cancer (HNPCC). It has been reported that loss of heterozygosity (LOH) at the LGR region occurs through a gene conversion mechanism in tumors from MLH1/MSH2 deletion carriers; however, the converted tracts were delineated only by extragenic microsatellite markers. We sought to determine the frequency of LGRs in Slovak HNPCC patients and to study LOH in tumors from LGR carriers at the LGR region, as well as at other heterozygous markers within the gene to more precisely define conversion tracts. Methods The main MMR genes responsible for HNPCC, MLH1, MSH2, MSH6, and PMS2, were analyzed by MLPA (multiplex ligation-dependent probe amplification) in a total of 37 unrelated HNPCC-suspected patients whose MLH1/MSH2 genes gave negative results in previous sequencing experiments. An LOH study was performed on six tumors from LGR carriers by combining MLPA to assess LOH at LGR regions and sequencing to examine LOH at 28 SNP markers from the MLH1 and MSH2 genes. Results We found six rearrangements in the MSH2 gene (five deletions and dup5-6), and one aberration in the MLH1 gene (del5-6). The MSH2 deletions were of three types (del1, del1-3, del1-7). We detected LOH at the LGR region in the single MLH1 case, which was determined in a previous study to be LOH-negative in the intragenic D3S1611 marker. Three tumors displayed LOH of at least one SNP marker, including two cases that were LOH-negative at the LGR region. Conclusion LGRs accounted for 25% of germline MMR mutations identified in 28 Slovakian HNPCC families. A high frequency of LGRs among the MSH2 mutations provides a rationale for a MLPA screening of the Slovakian HNPCC families prior scanning by DNA sequencing. LOH at part of the informative loci confined to the MLH1 or MSH2 gene (heterozygous LGR region, SNP, or microsatellite) is a novel finding and can be regarded as a partial LOH. The conversion begins within the gene, and the details of conversion tracts are discussed for each case.
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Affiliation(s)
- Katarina Zavodna
- Laboratory of Cancer Genetics, Cancer Research Institute of Slovak Academy of Sciences, Vlarska 7, 833 91 Bratislava, Slovak Republic.
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Gylling A, Ridanpää M, Vierimaa O, Aittomäki K, Avela K, Kääriäinen H, Laivuori H, Pöyhönen M, Sallinen SL, Wallgren-Pettersson C, Järvinen HJ, Mecklin JP, Peltomäki P. Large genomic rearrangements and germline epimutations in Lynch syndrome. Int J Cancer 2009; 124:2333-40. [PMID: 19173287 DOI: 10.1002/ijc.24230] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In one-third of families fulfilling the Amsterdam criteria for hereditary nonpolyposis colorectal cancer/Lynch syndrome, and a majority of those not fulfilling these criteria point mutations in DNA mismatch repair (MMR) genes are not found. The role of large genomic rearrangements and germline epimutations in MLH1, MSH2 and MSH6 was evaluated in 2 such cohorts. All 45 index patients were mutation-negative by genomic sequencing and testing for a prevalent population-specific founder mutation, and selectively lacked MMR protein expression in tumor tissue. Eleven patients ("research cohort") represented 11 mutation-negative families among 81 verified or putative Lynch syndrome families from the nation-wide Hereditary Colorectal Cancer Registry of Finland. Thirty-four patients from 33 families ("clinic-based cohort") represented suspected Lynch syndrome patients tested for MMR gene mutations in a diagnostic laboratory during 2004-2007. Multiplex ligation-dependent probe amplification (MLPA) and methylation-specific (MS)-MLPA were used to detect rearrangements and epimutations, respectively. Large genomic deletions occurred in 12/45 patients (27%), being present in 3/25 (12%), 9/16 (56%) and 0/4 (0%) among index patients lacking MLH1, MSH2 or MSH6 expression, respectively. Germline epimutations of MLH1, one of which coexisted with a genomic deletion, occurred in 2 patients (4%) and were accompanied by monoallelic expression in mRNA. Large genomic deletions (mainly MSH2) and germline epimutations (MLH1) together explain a significant fraction of point mutation-negative families suspected of Lynch syndrome and are associated with characteristic clinical and family features. Our findings have important implications in the diagnosis and management of such families.
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Affiliation(s)
- Annette Gylling
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland.
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Oliveira C, Senz J, Kaurah P, Pinheiro H, Sanges R, Haegert A, Corso G, Schouten J, Fitzgerald R, Vogelsang H, Keller G, Dwerryhouse S, Grimmer D, Chin SF, Yang HK, Jackson CE, Seruca R, Roviello F, Stupka E, Caldas C, Huntsman D. Germline CDH1 deletions in hereditary diffuse gastric cancer families. Hum Mol Genet 2009; 18:1545-55. [PMID: 19168852 PMCID: PMC2667284 DOI: 10.1093/hmg/ddp046] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Germline CDH1 point or small frameshift mutations can be identified in 30-50% of hereditary diffuse gastric cancer (HDGC) families. We hypothesized that CDH1 genomic rearrangements would be found in HDGC and identified 160 families with either two gastric cancers in first-degree relatives and with at least one diffuse gastric cancer (DGC) diagnosed before age 50, or three or more DGC in close relatives diagnosed at any age. Sixty-seven carried germline CDH1 point or small frameshift mutations. We screened germline DNA from the 93 mutation negative probands for large genomic rearrangements by Multiplex Ligation-Dependent Probe Amplification. Potential deletions were validated by RT-PCR and breakpoints cloned using a combination of oligo-CGH-arrays and long-range-PCR. In-silico analysis of the CDH1 locus was used to determine a potential mechanism for these rearrangements. Six of 93 (6.5%) previously described mutation negative HDGC probands, from low GC incidence populations (UK and North America), carried genomic deletions (UK and North America). Two families carried an identical deletion spanning 193 593 bp, encompassing the full CDH3 sequence and CDH1 exons 1 and 2. Other deletions affecting exons 1, 2, 15 and/or 16 were identified. The statistically significant over-representation of Alus around breakpoints indicates it as a likely mechanism for these deletions. When all mutations and deletions are considered, the overall frequency of CDH1 alterations in HDGC is approximately 46% (73/160). CDH1 large deletions occur in 4% of HDGC families by mechanisms involving mainly non-allelic homologous recombination in Alu repeat sequences. As the finding of pathogenic CDH1 mutations is useful for management of HDGC families, screening for deletions should be offered to at-risk families.
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Affiliation(s)
- Carla Oliveira
- Institute of Molecular Pathology and Immunology, University of Porto, Portugal
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da Silva FCC, Valentin MD, Ferreira FDO, Carraro DM, Rossi BM. Mismatch repair genes in Lynch syndrome: a review. SAO PAULO MED J 2009; 127:46-51. [PMID: 19466295 PMCID: PMC10969316 DOI: 10.1590/s1516-31802009000100010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2008] [Revised: 12/07/2008] [Accepted: 12/09/2008] [Indexed: 01/01/2023] Open
Abstract
Lynch syndrome represents 1-7% of all cases of colorectal cancer and is an autosomal-dominant inherited cancer predisposition syndrome caused by germline mutations in deoxyribonucleic acid (DNA) mismatch repair genes. Since the discovery of the major human genes with DNA mismatch repair function, mutations in five of them have been correlated with susceptibility to Lynch syndrome: mutS homolog 2 (MSH2); mutL homolog 1 (MLH1); mutS homolog 6 (MSH6); postmeiotic segregation increased 2 (PMS2); and postmeiotic segregation increased 1 (PMS1). It has been proposed that one additional mismatch repair gene, mutL homolog 3 (MLH3), also plays a role in Lynch syndrome predisposition, but the clinical significance of mutations in this gene is less clear. According to the InSiGHT database (International Society for Gastrointestinal Hereditary Tumors), approximately 500 different LS-associated mismatch repair gene mutations are known, primarily involving MLH1 (50%) and MSH2 (40%), while others account for 10%. Much progress has been made in understanding the molecular basis of Lynch Syndrome. Molecular characterization will be the most accurate way of defining Lynch syndrome and will provide predictive information of greater accuracy regarding the risks of colon and extracolonic cancer and enable optimal cancer surveillance regimens.
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Affiliation(s)
| | | | - Fábio de Oliveira Ferreira
- MD, PhD. Surgeon at Hospital AC Camargo and researcher in the Research Center of Hospital AC Camargo, São Paulo, Brazil.
| | - Dirce Maria Carraro
- PhD. Researcher in the Research Center of Hospital AC Camargo, São Paulo, Brazil.
| | - Benedito Mauro Rossi
- MD, PhD. Surgeon at Hospital AC Camargo and researcher in the Research Center of Hospital AC Camargo, São Paulo, Brazil.
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Miyashita K, Fujii K, Yamada Y, Hattori H, Taguchi K, Yamanaka T, Yoshida MA, Okamura J, Oda S, Muta K, Nawata H, Takayanagi R, Uike N. Frequent microsatellite instability in non-Hodgkin lymphomas irresponsive to chemotherapy. Leuk Res 2008; 32:1183-95. [DOI: 10.1016/j.leukres.2007.11.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2007] [Revised: 11/13/2007] [Accepted: 11/14/2007] [Indexed: 11/29/2022]
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Pineda M, Castellsagué E, Musulén E, Llort G, Frebourg T, Baert-Desurmont S, González S, Capellá G, Blanco I. Non-Hodgkin lymphoma related to hereditary nonpolyposis colorectal cancer in a patient with a novel heterozygous complex deletion in theMSH2 gene. Genes Chromosomes Cancer 2008; 47:326-32. [DOI: 10.1002/gcc.20536] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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