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Zhang Y, Win AK, Makalic E, Buchanan DD, Pai RK, Phipps AI, Rosty C, Boussioutas A, Karahalios A, Jenkins MA. Associations between pathological features and risk of metachronous colorectal cancer. Int J Cancer 2024. [PMID: 38676439 DOI: 10.1002/ijc.34979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 03/07/2024] [Accepted: 04/02/2024] [Indexed: 04/28/2024]
Abstract
Survivors of colorectal cancer (CRC) are at risk of developing another primary colorectal cancer - metachronous CRC. Understanding which pathological features of the first tumour are associated with risk of metachronous CRC might help tailor existing surveillance guidelines. Population-based CRC cases were recruited from the United States, Canada and Australia between 1997 and 2012 and followed prospectively until 2022 by the Colon Cancer Family Registry. Metachronous CRC was defined as a new primary CRC diagnosed at least 1 year after the initial CRC. Those with the genetic cancer predisposition Lynch syndrome or MUTYH mutation carriers were excluded. Cox regression models were fitted to estimate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) for the associations. Of 6085 CRC cases, 138 (2.3%) were diagnosed with a metachronous CRC over a median follow-up time of 12 years (incidence: 2.0 per 1000 person-years). CRC cases with a synchronous CRC were 3.4-fold more likely to develop a metachronous CRC (adjusted HR: 3.36, 95% CI: 1.89-5.98) than those without a synchronous tumour. CRC cases with MMR-deficient tumours had a 72% increased risk of metachronous CRC (adjusted HR: 1.72, 95% CI: 1.11-2.64) compared to those with MMR-proficient tumours. Compared to cases who had an adenocarcinoma histologic type, those with an undifferentiated histologic type were 77% less likely to develop a metachronous CRC (adjusted HR: 0.23, 95% CI: 0.06-0.94). Existing surveillance guidelines for CRC survivors could be updated to include increased surveillance for those whose first CRC was diagnosed with a synchronous CRC or was MMR-deficient.
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Affiliation(s)
- Ye Zhang
- Center for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, University of Melbourne, Melbourne, Victoria, Australia
| | - Aung Ko Win
- Center for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, University of Melbourne, Melbourne, Victoria, Australia
- Genomic Medicine and Family Cancer Clinic, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Enes Makalic
- Center for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Daniel D Buchanan
- Center for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, University of Melbourne, Melbourne, Victoria, Australia
- Genomic Medicine and Family Cancer Clinic, Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Rish K Pai
- Department of Pathology and Laboratory Medicine, Mayo Clinic Arizona, Scottsdale, Arizona, USA
| | - Amanda I Phipps
- Department of Epidemiology, University of Washington, Seattle, Washington, USA
- Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, Washington, USA
| | | | - Alex Boussioutas
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Parkville, Victoria, Australia
- Department of Gastroenterology, The Alfred, Monash University, Melbourne, Victoria, Australia
| | - Amalia Karahalios
- Center for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Mark A Jenkins
- Center for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, University of Melbourne, Melbourne, Victoria, Australia
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2
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Walker R, Mahmood K, Joo JE, Clendenning M, Georgeson P, Como J, Joseland S, Preston SG, Antill Y, Austin R, Boussioutas A, Bowman M, Burke J, Campbell A, Daneshvar S, Edwards E, Gleeson M, Goodwin A, Harris MT, Henderson A, Higgins M, Hopper JL, Hutchinson RA, Ip E, Isbister J, Kasem K, Marfan H, Milnes D, Ng A, Nichols C, O'Connell S, Pachter N, Pope BJ, Poplawski N, Ragunathan A, Smyth C, Spigelman A, Storey K, Susman R, Taylor JA, Warwick L, Wilding M, Williams R, Win AK, Walsh MD, Macrae FA, Jenkins MA, Rosty C, Winship IM, Buchanan DD. A tumor focused approach to resolving the etiology of DNA mismatch repair deficient tumors classified as suspected Lynch syndrome. J Transl Med 2023; 21:282. [PMID: 37101184 PMCID: PMC10134620 DOI: 10.1186/s12967-023-04143-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 04/19/2023] [Indexed: 04/28/2023] Open
Abstract
Routine screening of tumors for DNA mismatch repair (MMR) deficiency (dMMR) in colorectal (CRC), endometrial (EC) and sebaceous skin (SST) tumors leads to a significant proportion of unresolved cases classified as suspected Lynch syndrome (SLS). SLS cases (n = 135) were recruited from Family Cancer Clinics across Australia and New Zealand. Targeted panel sequencing was performed on tumor (n = 137; 80×CRCs, 33×ECs and 24xSSTs) and matched blood-derived DNA to assess for microsatellite instability status, tumor mutation burden, COSMIC tumor mutational signatures and to identify germline and somatic MMR gene variants. MMR immunohistochemistry (IHC) and MLH1 promoter methylation were repeated. In total, 86.9% of the 137 SLS tumors could be resolved into established subtypes. For 22.6% of these resolved SLS cases, primary MLH1 epimutations (2.2%) as well as previously undetected germline MMR pathogenic variants (1.5%), tumor MLH1 methylation (13.1%) or false positive dMMR IHC (5.8%) results were identified. Double somatic MMR gene mutations were the major cause of dMMR identified across each tumor type (73.9% of resolved cases, 64.2% overall, 70% of CRC, 45.5% of ECs and 70.8% of SSTs). The unresolved SLS tumors (13.1%) comprised tumors with only a single somatic (7.3%) or no somatic (5.8%) MMR gene mutations. A tumor-focused testing approach reclassified 86.9% of SLS into Lynch syndrome, sporadic dMMR or MMR-proficient cases. These findings support the incorporation of tumor sequencing and alternate MLH1 methylation assays into clinical diagnostics to reduce the number of SLS patients and provide more appropriate surveillance and screening recommendations.
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Affiliation(s)
- Romy Walker
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3010, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia
| | - Khalid Mahmood
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3010, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia
- Melbourne Bioinformatics, The University of Melbourne, Melbourne, VIC, 3051, Australia
| | - Jihoon E Joo
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3010, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia
| | - Mark Clendenning
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3010, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia
| | - Peter Georgeson
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3010, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia
| | - Julia Como
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3010, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia
| | - Sharelle Joseland
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3010, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia
| | - Susan G Preston
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3010, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia
| | - Yoland Antill
- Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC, 3050, Australia
- Familial Cancer Centre, Cabrini Health, Malvern, VIC, 3144, Australia
- Familial Cancer Centre, Monash Health, Clayton, VIC, 3168, Australia
- Faculty of Medicine, Dentistry and Health Sciences, Monash University, Melbourne, VIC, 3800, Australia
| | - Rachel Austin
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Brisbane, QLD, 4029, Australia
| | - Alex Boussioutas
- Central Clinical School, Monash University, Melbourne, VIC, 3004, Australia
- Department of Gastroenterology, The Alfred Hospital, Melbourne, VIC, 3004, Australia
- Department of Medicine, The Royal Melbourne Hospital, Melbourne, VIC, 3010, Australia
- Familial Cancer Centre, Peter MacCallum Cancer Centre, Parkville, VIC, 3000, Australia
| | - Michelle Bowman
- Familial Cancer Service, Westmead Hospital, Sydney, NSW, 2145, Australia
| | - Jo Burke
- Tasmanian Clinical Genetics Service, Royal Hobart Hospital, Hobart, TAS, 7000, Australia
- School of Medicine, University of Tasmania, Sandy Bay, TAS, 7005, Australia
| | - Ainsley Campbell
- Clinical Genetics Unit, Austin Health, Melbourne, VIC, 3084, Australia
| | - Simin Daneshvar
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3010, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia
| | - Emma Edwards
- Familial Cancer Service, Westmead Hospital, Sydney, NSW, 2145, Australia
| | | | - Annabel Goodwin
- Cancer Genetics Department, Royal Prince Alfred Hospital, Camperdown, NSW, 2050, Australia
- University of Sydney, Sydney, NSW, 2050, Australia
| | - Marion T Harris
- Monash Health Familial Cancer Centre, Clayton, VIC, 3168, Australia
| | - Alex Henderson
- Genetic Health Service, Wellington, Greater Wellington, 6242, New Zealand
- Wellington Hospital, Newtown, Greater Wellington, 6021, New Zealand
| | - Megan Higgins
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Brisbane, QLD, 4029, Australia
- University of Queensland, St Lucia, QLD, 4067, Australia
| | - John L Hopper
- Centre for Epidemiology and Biostatistics, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Ryan A Hutchinson
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3010, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia
| | - Emilia Ip
- Cancer Genetics Service, Liverpool Hospital, Liverpool, NSW, 2170, Australia
| | - Joanne Isbister
- Genomic Medicine and Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC, 3000, Australia
- Department of Medicine, The University of Melbourne, Melbourne, VIC, 3000, Australia
- Parkville Familial Cancer Centre, Peter McCallum Cancer Centre, Melbourne, VIC, 3000, Australia
| | - Kais Kasem
- Department of Clinical Pathology, Medicine Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Helen Marfan
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Brisbane, QLD, 4029, Australia
| | - Di Milnes
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Brisbane, QLD, 4029, Australia
- Royal Brisbane and Women's Hospital, Herston, QLD, 4029, Australia
| | - Annabelle Ng
- Cancer Genetics Department, Royal Prince Alfred Hospital, Camperdown, NSW, 2050, Australia
| | - Cassandra Nichols
- Genetic Services of Western Australia, King Edward Memorial Hospital, Perth, WA, 6008, Australia
| | - Shona O'Connell
- Monash Health Familial Cancer Centre, Clayton, VIC, 3168, Australia
| | - Nicholas Pachter
- Genetic Services of Western Australia, King Edward Memorial Hospital, Perth, WA, 6008, Australia
- Medical School, University of Western Australia, Perth, WA, 6009, Australia
- School of Medicine, Curtin University, Perth, WA, 6845, Australia
| | - Bernard J Pope
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3010, Australia
- Melbourne Bioinformatics, The University of Melbourne, Melbourne, VIC, 3051, Australia
| | - Nicola Poplawski
- Adult Genetics Unit, Royal Adelaide Hospital, Adelaide, SA, 5000, Australia
- Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, 5000, Australia
| | - Abiramy Ragunathan
- Familial Cancer Service, Westmead Hospital, Sydney, NSW, 2145, Australia
| | - Courtney Smyth
- Familial Cancer Centre, Monash Health, Clayton, VIC, 3168, Australia
| | - Allan Spigelman
- Hunter Family Cancer Service, Newcastle, NSW, 2298, Australia
- St Vincent's Cancer Genetics Unit, Sydney, NSW, 2290, Australia
- Surgical Professorial Unit, UNSW Clinical School of Clinical Medicine, Sydney, NSW, 2052, Australia
| | - Kirsty Storey
- Parkville Familial Cancer Centre, Peter McCallum Cancer Centre, Melbourne, VIC, 3000, Australia
| | - Rachel Susman
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Brisbane, QLD, 4029, Australia
| | - Jessica A Taylor
- Genomic Medicine and Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC, 3000, Australia
| | - Linda Warwick
- ACT Genetic Service, The Canberra Hospital, Woden, ACT, 2606, Australia
| | - Mathilda Wilding
- Familial Cancer Service, Royal North Shore Hospital, St Leonards, NSW, 2065, Australia
| | - Rachel Williams
- Prince of Wales Clinical School, UNSW Medicine and Health, UNSW Sydney, Kensington, NSW, 2052, Australia
- Prince of Wales Hereditary Cancer Centre, Prince of Wales Hospital, Randwick, NSW, 2031, Australia
| | - Aung K Win
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia
- Centre for Epidemiology and Biostatistics, The University of Melbourne, Melbourne, VIC, 3010, Australia
- Genomic Medicine and Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC, 3000, Australia
| | - Michael D Walsh
- Sullivan Nicolaides Pathology, Bowen Hills, QLD, 4006, Australia
- School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, 4072, Australia
| | - Finlay A Macrae
- Genomic Medicine and Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC, 3000, Australia
- Colorectal Medicine and Genetics, The Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Mark A Jenkins
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia
- Centre for Epidemiology and Biostatistics, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Christophe Rosty
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3010, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia
- Envoi Specialist Pathologists, Brisbane, QLD, 4059, Australia
- University of Queensland, Brisbane, QLD, 4072, Australia
| | - Ingrid M Winship
- Genomic Medicine and Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC, 3000, Australia
- Department of Medicine, The University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Daniel D Buchanan
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3010, Australia.
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, 3010, Australia.
- Genomic Medicine and Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC, 3000, Australia.
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3
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Walker R, Mahmood K, Joo JE, Clendenning M, Georgeson P, Como J, Joseland S, Preston SG, Antill Y, Austin R, Boussioutas A, Bowman M, Burke J, Campbell A, Daneshvar S, Edwards E, Gleeson M, Goodwin A, Harris MT, Henderson A, Higgins M, Hopper JL, Hutchinson RA, Ip E, Isbister J, Kasem K, Marfan H, Milnes D, Ng A, Nichols C, O’Connell S, Pachter N, Pope BJ, Poplawski N, Ragunathan A, Smyth C, Spigelman A, Storey K, Susman R, Taylor JA, Warwick L, Wilding M, Williams R, Win AK, Walsh MD, Macrae FA, Jenkins MA, Rosty C, Winship IM, Buchanan DD. A tumor focused approach to resolving the etiology of DNA mismatch repair deficient tumors classified as suspected Lynch syndrome. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.02.27.23285541. [PMID: 36909643 PMCID: PMC10002795 DOI: 10.1101/2023.02.27.23285541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Abstract
Routine screening of tumors for DNA mismatch repair (MMR) deficiency (dMMR) in colorectal (CRC), endometrial (EC) and sebaceous skin (SST) tumors leads to a significant proportion of unresolved cases classified as suspected Lynch syndrome (SLS). SLS cases (n=135) were recruited from Family Cancer Clinics across Australia and New Zealand. Targeted panel sequencing was performed on tumor (n=137; 80xCRCs, 33xECs and 24xSSTs) and matched blood-derived DNA to assess for microsatellite instability status, tumor mutation burden, COSMIC tumor mutational signatures and to identify germline and somatic MMR gene variants. MMR immunohistochemistry (IHC) and MLH1 promoter methylation were repeated. In total, 86.9% of the 137 SLS tumors could be resolved into established subtypes. For 22.6% of these resolved SLS cases, primary MLH1 epimutations (2.2%) as well as previously undetected germline MMR pathogenic variants (1.5%), tumor MLH1 methylation (13.1%) or false positive dMMR IHC (5.8%) results were identified. Double somatic MMR gene mutations were the major cause of dMMR identified across each tumor type (73.9% of resolved cases, 64.2% overall, 70% of CRC, 45.5% of ECs and 70.8% of SSTs). The unresolved SLS tumors (13.1%) comprised tumors with only a single somatic (7.3%) or no somatic (5.8%) MMR gene mutations. A tumor-focused testing approach reclassified 86.9% of SLS into Lynch syndrome, sporadic dMMR or MMR-proficient cases. These findings support the incorporation of tumor sequencing and alternate MLH1 methylation assays into clinical diagnostics to reduce the number of SLS patients and provide more appropriate surveillance and screening recommendations.
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Affiliation(s)
- Romy Walker
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, VIC 3010, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
| | - Khalid Mahmood
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, VIC 3010, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
- Melbourne Bioinformatics, The University of Melbourne, Melbourne, VIC 3051, Australia
| | - Jihoon E. Joo
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, VIC 3010, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
| | - Mark Clendenning
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, VIC 3010, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
| | - Peter Georgeson
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, VIC 3010, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
| | - Julia Como
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, VIC 3010, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
| | - Sharelle Joseland
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, VIC 3010, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
| | - Susan G. Preston
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, VIC 3010, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
| | - Yoland Antill
- Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC 3050, Australia
- Familial Cancer Centre, Cabrini Health, Malvern, VIC 3144, Australia
- Familial Cancer Centre, Monash Health, Clayton, VIC 3168, Australia
- Faculty of Medicine, Dentistry and Health Sciences, Monash University, Melbourne, VIC 3800, Australia
| | - Rachel Austin
- Genetic Health Queensland, Royal Brisbane and Women’s Hospital, Brisbane, QLD 4029, Australia
| | - Alex Boussioutas
- Central Clinical School, Monash University, Melbourne, VIC 3004, Australia
- Department of Gastroenterology, The Alfred Hospital, Melbourne, VIC 3004, Australia
- Department of Medicine, The Royal Melbourne Hospital, Melbourne, VIC 3010, Australia
- Familial Cancer Centre, Peter MacCallum Cancer Centre, Parkville, VIC 3000, Australia
| | - Michelle Bowman
- Familial Cancer Service, Westmead Hospital, Sydney, NSW 2145, Australia
| | - Jo Burke
- Tasmanian Clinical Genetics Service, Royal Hobart Hospital, Hobart, TAS 7000, Australia
- School of Medicine, University of Tasmania, Sandy Bay, TAS 7005 Australia
| | - Ainsley Campbell
- Clinical Genetics Unit, Austin Health, Melbourne, VIC 3084, Australia
| | - Simin Daneshvar
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, VIC 3010, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
| | - Emma Edwards
- Familial Cancer Service, Westmead Hospital, Sydney, NSW 2145, Australia
| | | | - Annabel Goodwin
- Cancer Genetics Department, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia
- University of Sydney, Sydney, NSW 2050, Australia
| | - Marion T. Harris
- Monash Health Familial Cancer Centre, Clayton, VIC 3168, Australia
| | - Alex Henderson
- Genetic Health Service, Wellington, Greater Wellington, 6242, New Zealand
- Wellington Hospital, Newtown, Greater Wellington 6021, New Zealand
| | - Megan Higgins
- Genetic Health Queensland, Royal Brisbane and Women’s Hospital, Brisbane, QLD 4029, Australia
- University of Queensland, St Lucia, QLD 4067, Australia
| | - John L. Hopper
- Centre for Epidemiology and Biostatistics, The University of Melbourne, Parkville, Melbourne, Victoria, 3010, Australia
| | - Ryan A. Hutchinson
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, VIC 3010, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
| | - Emilia Ip
- Cancer Genetics service, Liverpool Hospital, Liverpool, NSW 2170, Australia
| | - Joanne Isbister
- Genomic Medicine and Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC 3000, Australia
- Department of Medicine, The University of Melbourne, VIC 3000, Australia
- Parkville Familial Cancer Centre, Peter McCallum Cancer Centre, Melbourne, VIC 3000, Australia
| | - Kais Kasem
- Department of Clinical Pathology, Medicine Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Helen Marfan
- Genetic Health Queensland, Royal Brisbane and Women’s Hospital, Brisbane, QLD 4029, Australia
| | - Di Milnes
- Genetic Health Queensland, Royal Brisbane and Women’s Hospital, Brisbane, QLD 4029, Australia
- Royal Brisbane and Women’s Hospital, Herston, QLD 4029, Australia
| | - Annabelle Ng
- Cancer Genetics Department, Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia
| | - Cassandra Nichols
- Genetic Services of Western Australia, King Edward Memorial Hospital, Perth, WA 6008, Australia
| | - Shona O’Connell
- Monash Health Familial Cancer Centre, Clayton, VIC 3168, Australia
| | - Nicholas Pachter
- Genetic Services of Western Australia, King Edward Memorial Hospital, Perth, WA 6008, Australia
- Medical School, University of Western Australia, Perth, WA 6009, Australia
- School of Medicine, Curtin University, Perth, WA 6845, Australia
| | - Bernard J. Pope
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, VIC 3010, Australia
- Melbourne Bioinformatics, The University of Melbourne, Melbourne, VIC 3051, Australia
| | - Nicola Poplawski
- Adult Genetics Unit, Royal Adelaide Hospital, Adelaide, SA 5000, Australia
- Adelaide Medical School, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA 5000, Australia
| | | | - Courtney Smyth
- Familial Cancer Centre, Monash Health, Clayton, VIC 3168, Australia
| | - Allan Spigelman
- Hunter Family Cancer Service, Newcastle, NSW 2298, Australia
- St Vincent’s Cancer Genetics Unit, Sydney, NSW 2290, Australia
- Surgical Professorial Unit, UNSW Clinical School of Clinical Medicine, Sydney, NSW 2052, Australia
| | - Kirsty Storey
- Parkville Familial Cancer Centre, Peter McCallum Cancer Centre, Melbourne, VIC 3000, Australia
| | - Rachel Susman
- Genetic Health Queensland, Royal Brisbane and Women’s Hospital, Brisbane, QLD 4029, Australia
| | - Jessica A. Taylor
- Genomic Medicine and Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC 3000, Australia
| | - Linda Warwick
- ACT Genetic Service, The Canberra Hospital, Woden, ACT 2606, Australia
| | - Mathilda Wilding
- Familial Cancer Service, Royal North Shore Hospital, St Leonards, NSW 2065, Australia
| | - Rachel Williams
- Prince of Wales Clinical School, UNSW Medicine and Health, UNSW Sydney, Kensington, NSW 2052, Australia
- Prince of Wales Hereditary Cancer Centre, Prince of Wales Hospital, Randwick, NSW 2031, Australia
| | - Aung K. Win
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
- Centre for Epidemiology and Biostatistics, The University of Melbourne, Parkville, Melbourne, Victoria, 3010, Australia
- Genomic Medicine and Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC 3000, Australia
| | - Michael D. Walsh
- Sullivan Nicolaides Pathology, Bowen Hills, QLD 4006, Australia
- School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD 4072, Australia
| | - Finlay A. Macrae
- Genomic Medicine and Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC 3000, Australia
- Colorectal Medicine and Genetics, The Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Mark A. Jenkins
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
- Centre for Epidemiology and Biostatistics, The University of Melbourne, Parkville, Melbourne, Victoria, 3010, Australia
| | - Christophe Rosty
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, VIC 3010, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
- Envoi Specialist Pathologists, Brisbane, QLD 4059, Australia
- University of Queensland, Brisbane, QLD 4072, Australia
| | - Ingrid M. Winship
- Genomic Medicine and Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC 3000, Australia
- Department of Medicine, The University of Melbourne, VIC 3000, Australia
| | - Daniel D. Buchanan
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, VIC 3010, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC 3010, Australia
- Genomic Medicine and Familial Cancer Centre, Royal Melbourne Hospital, Parkville, VIC 3000, Australia
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Nugroho PP, Ghozali SAS, Buchanan DD, Pisano MI, Reece JC. Risk of cancer in individuals with Lynch-like syndrome and their families: a systematic review. J Cancer Res Clin Oncol 2023; 149:25-46. [PMID: 36251064 PMCID: PMC9889410 DOI: 10.1007/s00432-022-04397-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 10/05/2022] [Indexed: 02/04/2023]
Abstract
BACKGROUND Lynch-like syndrome (LLS) tumors have similar clinicopathological features to Lynch syndrome (LS) tumors but have no identifiable pathogenic germline mismatch repair gene variant. However, cancer risks in LLS patients and first-degree relatives (FDRs) are not well defined. METHODS To clarify LLS-associated cancer risks, a systematic review of all studies examining all cancer risks in LLS was performed. Searching of Medline, Embase, Pubmed, Cochrane and CINAHL databases and reference/citation checking identified relevant studies published between January 1, 1980 and February 11, 2021. Joanna Briggs Institute Appraisal Tools assessed the risk of bias. RESULTS Six studies (five cohort/one cross-sectional) were eligible for study inclusion. One study found no difference in colorectal cancer (CRC) incidence between LLS and LS patients or CRC risks at aged 70 years. Three studies found CRC incidence in LLS FDRs was higher than the general population but lower than LS FDRs. Two studies showed no difference in CRC diagnosis age between LLS patients and LS patients. Endometrial cancer risks in LLS patients were higher than the general population but lower than LS patients. CONCLUSION Evidence of elevated CRC risks in LLS patients and FDRs supports increased colonoscopy surveillance strategies for LLS patients and FDRs in line with current recommendations for LS. Due to heterogeneity amongst LLS populations, extended intervals between screening may be advised for low-risk families. Studies to resolve the molecular characterization and definition of LLS are needed to clarify cancer risks associated with LLS which in turn may individualize surveillance strategies for LLS patients and families.
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Affiliation(s)
- Pandu P Nugroho
- Faculty of Medicine, Universitas Indonesia, Depok, West Java, Indonesia
- Melbourne Medical School, The University of Melbourne, Parkville, VIC, Australia
| | - Siti Alyaa S Ghozali
- Faculty of Medicine, Universitas Indonesia, Depok, West Java, Indonesia
- Melbourne Medical School, The University of Melbourne, Parkville, VIC, Australia
| | - Daniel D Buchanan
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Melbourne Medical School, The University of Melbourne, Parkville, VIC, Australia
- University of Melbourne Centre for Cancer Research, Parkville, VIC, Australia
- Genomic Medicine and Family Cancer Clinic, Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Mia I Pisano
- Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Jeanette C Reece
- Neuroepidemiology Unit, Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Level 3 207 Bouverie Street, Parkville, VIC, 3010, Australia.
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5
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Eikenboom EL, Moen S, van Leeuwen L, Geurts-Giele WR, Tops CM, van Ham TJ, Dinjens WN, Dubbink HJ, Spaander MC, Wagner A. Unexplained mismatch repair deficiency: Case closed. HGG ADVANCES 2022; 4:100167. [PMID: 36624813 PMCID: PMC9823207 DOI: 10.1016/j.xhgg.2022.100167] [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: 07/22/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
To identify Lynch syndrome (LS) carriers, DNA mismatch repair (MMR) immunohistochemistry (IHC) is performed on colorectal cancers (CRCs). Upon subsequent LS diagnostics, MMR deficiency (MMRd) sometimes remains unexplained (UMMRd). Recently, the importance of complete LS diagnostics to explain UMMRd, involving MMR methylation, germline, and somatic analyses, was stressed. To explore why some MMRd CRCs remain unsolved, we performed a systematic review of the literature and mapped patients with UMMRd diagnosed in our center. A systematic literature search was performed in Ovid Medline, Embase, Web of Science, Cochrane CENTRAL, and Google Scholar for articles on UMMRd CRCs after complete LS diagnostics published until December 15, 2021. Additionally, UMMRd CRCs diagnosed in our center since 1993 were mapped. Of 754 identified articles, 17 were included, covering 74 patients with UMMRd. Five CRCs were microsatellite stable. Upon complete diagnostics, 39 patients had single somatic MMR hits, and six an MMR germline variant of unknown significance (VUS). Ten had somatic pathogenic variants (PVs) in POLD1, MLH3, MSH3, and APC. The remaining 14 patients were the only identifiable cases in the literature without a plausible identified cause of the UMMRd. Of those, nine were suspected to have LS. In our center, complete LS diagnostics in approximately 5,000 CRCs left seven MMRd CRCs unexplained. All had a somatic MMR hit or MMR germline VUS, indicative of a missed second MMR hit. In vitually all patients with UMMRd, complete LS diagnostics suggest MMR gene involvement. Optimizing detection of currently undetectable PVs and VUS interpretation might explain all UMMRd CRCs, considering UMMRd a case closed.
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Affiliation(s)
- Ellis L. Eikenboom
- Department of Clinical Genetics, Erasmus MC Cancer Institute, University Medical Center Rotterdam, 3015 CE Rotterdam, the Netherlands,Department of Gastroenterology and Hepatology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, 3015 CE Rotterdam, the Netherlands
| | - Sarah Moen
- Department of Gastroenterology and Hepatology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, 3015 CE Rotterdam, the Netherlands
| | - Lotte van Leeuwen
- Department of Clinical Genetics, Erasmus MC Cancer Institute, University Medical Center Rotterdam, 3015 CE Rotterdam, the Netherlands
| | - Willemina R.R. Geurts-Giele
- Department of Clinical Genetics, Erasmus MC Cancer Institute, University Medical Center Rotterdam, 3015 CE Rotterdam, the Netherlands
| | - Carli M.J. Tops
- Department of Clinical Genetics, Leiden University Medical Center, 2333 ZA Leiden, the Netherlands
| | - Tjakko J. van Ham
- Department of Clinical Genetics, Erasmus MC Cancer Institute, University Medical Center Rotterdam, 3015 CE Rotterdam, the Netherlands
| | - Winand N.M. Dinjens
- Department of Pathology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, 3015 CE Rotterdam, the Netherlands
| | - Hendrikus J. Dubbink
- Department of Pathology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, 3015 CE Rotterdam, the Netherlands
| | - Manon C.W. Spaander
- Department of Gastroenterology and Hepatology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, 3015 CE Rotterdam, the Netherlands
| | - Anja Wagner
- Department of Clinical Genetics, Erasmus MC Cancer Institute, University Medical Center Rotterdam, 3015 CE Rotterdam, the Netherlands,Corresponding author
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6
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Te Paske IBAW, Mensenkamp AR, Neveling K, Hoogerbrugge N, Ligtenberg MJL, De Voer RM. Noncoding Aberrations in Mismatch Repair Genes Underlie a Substantial Part of the Missing Heritability in Lynch Syndrome. Gastroenterology 2022; 163:1691-1694.e7. [PMID: 36037994 DOI: 10.1053/j.gastro.2022.08.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/15/2022] [Accepted: 08/22/2022] [Indexed: 12/02/2022]
Affiliation(s)
- Iris B A W Te Paske
- Department of Human Genetics, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen, the Netherlands
| | - Arjen R Mensenkamp
- Department of Human Genetics, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen, the Netherlands
| | - Kornelia Neveling
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, the Netherlands
| | | | - Nicoline Hoogerbrugge
- Department of Human Genetics, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen, the Netherlands
| | - Marjolijn J L Ligtenberg
- Department of Human Genetics, Department of Pathology, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen, the Netherlands
| | - Richarda M De Voer
- Department of Human Genetics, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen, the Netherlands.
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7
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Venkataramany AS, Schieffer KM, Lee K, Cottrell CE, Wang PY, Mardis ER, Cripe TP, Chandler DS. Alternative RNA Splicing Defects in Pediatric Cancers: New Insights in Tumorigenesis and Potential Therapeutic Vulnerabilities. Ann Oncol 2022; 33:578-592. [PMID: 35339647 DOI: 10.1016/j.annonc.2022.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Compared to adult cancers, pediatric cancers are uniquely characterized by a genomically stable landscape and lower tumor mutational burden. However, alternative splicing, a global cellular process that produces different mRNA/protein isoforms from a single mRNA transcript, has been increasingly implicated in the development of pediatric cancers. DESIGN We review the current literature on the role of alternative splicing in adult cancer, cancer predisposition syndromes, and pediatric cancers. We also describe multiple splice variants identified in adult cancers and confirmed through comprehensive genomic profiling in our institutional cohort of rare, refractory and relapsed pediatric and adolescent young adult cancer patients. Finally, we summarize the contributions of alternative splicing events to neoantigens and chemoresistance and prospects for splicing-based therapies. RESULTS Published dysregulated splicing events can be categorized as exon inclusion, exon exclusion, splicing factor upregulation, or splice site alterations. We observe these phenomena in cancer predisposition syndromes (Lynch syndrome, Li-Fraumeni syndrome, CHEK2) and pediatric leukemia (B-ALL), sarcomas (Ewing sarcoma, rhabdomyosarcoma, osteosarcoma), retinoblastoma, Wilms tumor, and neuroblastoma. Within our institutional cohort, we demonstrate splice variants in key regulatory genes (CHEK2, TP53, PIK3R1, MDM2, KDM6A, NF1) that resulted in exon exclusion or splice site alterations, which were predicted to impact functional protein expression and promote tumorigenesis. Differentially spliced isoforms and splicing proteins also impact neoantigen creation and treatment resistance, such as imatinib or glucocorticoid regimens. Additionally, splice-altering strategies with the potential to change the therapeutic landscape of pediatric cancers include antisense oligonucleotides, adeno-associated virus gene transfers, and small molecule inhibitors. CONCLUSIONS Alternative splicing plays a critical role in the formation and growth of pediatric cancers, and our institutional cohort confirms and highlights the broad spectrum of affected genes in a variety of cancers. Further studies that elucidate the mechanisms of disease-inducing splicing events will contribute toward the development of novel therapeutics.
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Affiliation(s)
- A S Venkataramany
- Biomedical Sciences Graduate Program, The Ohio State University, Columbus, Ohio, United States; Medical Scientist Training Program, The Ohio State University, Columbus, Ohio, United States
| | - K M Schieffer
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, Ohio, United States
| | - K Lee
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, Ohio, United States; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, United States; Department of Pathology, The Ohio State University College of Medicine, Columbus, Ohio, United States
| | - C E Cottrell
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, Ohio, United States; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, United States; Department of Pathology, The Ohio State University College of Medicine, Columbus, Ohio, United States
| | - P Y Wang
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, United States; Center for Childhood Cancer and Blood Diseases, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States
| | - E R Mardis
- The Steve and Cindy Rasmussen Institute for Genomic Medicine, Nationwide Children's Hospital, Columbus, Ohio, United States; Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, United States
| | - T P Cripe
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, Ohio, United States; Center for Childhood Cancer and Blood Diseases, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States; Division of Hematology, Oncology and Blood and Marrow Transplant, Department of Pediatrics, The Ohio State University, Columbus, Ohio, United States
| | - D S Chandler
- Center for Childhood Cancer and Blood Diseases, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States; Molecular, Cellular and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, Ohio, United States.
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8
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Lynch-like Syndrome: Potential Mechanisms and Management. Cancers (Basel) 2022; 14:cancers14051115. [PMID: 35267422 PMCID: PMC8909420 DOI: 10.3390/cancers14051115] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/20/2022] [Accepted: 02/21/2022] [Indexed: 02/05/2023] Open
Abstract
Simple Summary Lynch-like syndrome (LLS) is defined as colorectal cancer cases with microsatellite instability (MSI) and loss of expression of MLH1, MSH2, MSH6, or PMS2 by immunohistochemistry (IHC) in the absence of a germline mutation in these genes that cannot be explained by BRAF mutation or MLH1 hypermethylation. The application of the universal strategy for the diagnosis of Lynch syndrome (LS) in all CRCs is leading to an increase in the incidence of cases of LLS. It has been described that risk of cancer in relatives of LLS patients is in between of that found in Lynch syndrome families and sporadic cases. That makes LLS patients and their families a challenging group for which the origin of CRC is unknown, being a mixture between unidentified hereditary CRC and sporadic cases. The potential causes of LLS are discussed in this review, as well as methods for identification of truly hereditary cases. Abstract Lynch syndrome is an autosomal dominant disorder caused by germline mutations in DNA mismatch repair (MMR) system genes, such as MLH1, MSH2, MSH6, or PMS2. It is the most common hereditary colorectal cancer syndrome. Screening is regularly performed by using microsatellite instability (MSI) or immunohistochemistry for the MMR proteins in tumor samples. However, in a proportion of cases, MSI is found or MMR immunohistochemistry is impaired in the absence of a germline mutation in MMR genes, BRAF mutation, or MLH1 hypermethylation. These cases are defined as Lynch-like syndrome. Patients with Lynch-like syndrome represent a mixture of truly hereditary and sporadic cases, with a risk of colorectal cancer in first-degree relatives that is between the risk of Lynch syndrome in families and relatives of sporadic colon cancer cases. Although multiple approaches have been suggested to distinguish between hereditary and sporadic cases, a homogeneous testing protocol and consensus on the adequate classification of these patients is still lacking. For this reason, management of Lynch-like syndrome and prevention of cancer in these families is clinically challenging. This review explains the concept of Lynch-like syndrome, potential mechanisms for its development, and methods for adequately distinguishing between sporadic and hereditary cases of this entity.
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9
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Keegan NP, Wilton SD, Fletcher S. Analysis of Pathogenic Pseudoexons Reveals Novel Mechanisms Driving Cryptic Splicing. Front Genet 2022; 12:806946. [PMID: 35140743 PMCID: PMC8819188 DOI: 10.3389/fgene.2021.806946] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 12/09/2021] [Indexed: 12/16/2022] Open
Abstract
Understanding pre-mRNA splicing is crucial to accurately diagnosing and treating genetic diseases. However, mutations that alter splicing can exert highly diverse effects. Of all the known types of splicing mutations, perhaps the rarest and most difficult to predict are those that activate pseudoexons, sometimes also called cryptic exons. Unlike other splicing mutations that either destroy or redirect existing splice events, pseudoexon mutations appear to create entirely new exons within introns. Since exon definition in vertebrates requires coordinated arrangements of numerous RNA motifs, one might expect that pseudoexons would only arise when rearrangements of intronic DNA create novel exons by chance. Surprisingly, although such mutations do occur, a far more common cause of pseudoexons is deep-intronic single nucleotide variants, raising the question of why these latent exon-like tracts near the mutation sites have not already been purged from the genome by the evolutionary advantage of more efficient splicing. Possible answers may lie in deep intronic splicing processes such as recursive splicing or poison exon splicing. Because these processes utilize intronic motifs that benignly engage with the spliceosome, the regions involved may be more susceptible to exonization than other intronic regions would be. We speculated that a comprehensive study of reported pseudoexons might detect alignments with known deep intronic splice sites and could also permit the characterisation of novel pseudoexon categories. In this report, we present and analyse a catalogue of over 400 published pseudoexon splice events. In addition to confirming prior observations of the most common pseudoexon mutation types, the size of this catalogue also enabled us to suggest new categories for some of the rarer types of pseudoexon mutation. By comparing our catalogue against published datasets of non-canonical splice events, we also found that 15.7% of pseudoexons exhibit some splicing activity at one or both of their splice sites in non-mutant cells. Importantly, this included seven examples of experimentally confirmed recursive splice sites, confirming for the first time a long-suspected link between these two splicing phenomena. These findings have the potential to improve the fidelity of genetic diagnostics and reveal new targets for splice-modulating therapies.
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Affiliation(s)
- Niall P. Keegan
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
- *Correspondence: Niall P. Keegan,
| | - Steve D. Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Perth, WA, Australia
- Centre for Neuromuscular and Neurological Disorders, Perron Institute for Neurological and Translational Science, The University of Western Australia, Perth, WA, Australia
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10
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Pope BJ, Clendenning M, Rosty C, Mahmood K, Georgeson P, Joo JE, Walker R, Hutchinson RA, Jayasekara H, Joseland S, Como J, Preston S, Spurdle AB, Macrae FA, Win AK, Hopper JL, Jenkins MA, Winship IM, Buchanan DD. Germline and Tumor Sequencing as a Diagnostic Tool To Resolve Suspected Lynch Syndrome. J Mol Diagn 2021; 23:358-371. [PMID: 33383211 PMCID: PMC7927277 DOI: 10.1016/j.jmoldx.2020.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 11/13/2020] [Accepted: 12/15/2020] [Indexed: 12/22/2022] Open
Abstract
Patients in whom mismatch repair (MMR)-deficient cancer develops in the absence of pathogenic variants of germline MMR genes or somatic hypermethylation of the MLH1 gene promoter are classified as having suspected Lynch syndrome (SLS). Germline whole-genome sequencing (WGS) and targeted and genome-wide tumor sequencing were applied to identify the underlying cause of tumor MMR deficiency in SLS. Germline WGS was performed on samples from 14 cancer-affected patients with SLS, including two sets of first-degree relatives. MMR genes were assessed for germline pathogenic variants, including complex structural rearrangements and noncoding variants. Tumor tissue was assessed for somatic MMR gene mutations using targeted, whole-exome sequencing or WGS. Germline WGS identified pathogenic MMR variants in 3 of the 14 cases (21.4%), including a 9.5-megabase inversion disrupting MSH2 in a mother and daughter. Excluding these 3 MMR carriers, tumor sequencing identified at least two somatic MMR gene mutations in 8 of 11 tumors tested (72.7%). In a second mother-daughter pair, a somatic cause of tumor MMR deficiency was supported by the presence of double somatic MSH2 mutations in their respective tumors. More than 70% of SLS cases had double somatic MMR mutations in the absence of germline pathogenic variants in the MMR or other DNA repair-related genes on WGS, and, therefore, were confidently assigned a noninherited cause of tumor MMR deficiency.
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Affiliation(s)
- Bernard J Pope
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia; Centre for Cancer Research, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, Victoria, Australia; Melbourne Bioinformatics, The University of Melbourne, Parkville, Victoria, Australia
| | - Mark Clendenning
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia; Centre for Cancer Research, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, Victoria, Australia
| | - Christophe Rosty
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia; Centre for Cancer Research, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, Victoria, Australia; Envoi Specialist Pathologists, Brisbane, Queensland, Australia; School of Medicine, University of Queensland, Herston, Queensland, Australia
| | - Khalid Mahmood
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia; Centre for Cancer Research, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, Victoria, Australia; Melbourne Bioinformatics, The University of Melbourne, Parkville, Victoria, Australia
| | - Peter Georgeson
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia; Centre for Cancer Research, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, Victoria, Australia
| | - Jihoon E Joo
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia; Centre for Cancer Research, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, Victoria, Australia
| | - Romy Walker
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia; Centre for Cancer Research, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, Victoria, Australia
| | - Ryan A Hutchinson
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia; Centre for Cancer Research, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, Victoria, Australia
| | - Harindra Jayasekara
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia; Centre for Cancer Research, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, Victoria, Australia; Division of Cancer Epidemiology, Cancer Council Victoria, Melbourne, Victoria, Australia
| | - Sharelle Joseland
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia; Centre for Cancer Research, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, Victoria, Australia
| | - Julia Como
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia; Centre for Cancer Research, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, Victoria, Australia
| | - Susan Preston
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia; Centre for Cancer Research, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, Victoria, Australia
| | - Amanda B Spurdle
- Molecular Cancer Epidemiology Laboratory, Berghofer Medical Research Institute, Queensland Institute of Medical Research, Brisbane, Queensland, Australia
| | - Finlay A Macrae
- Colorectal Medicine and Genetics, The Royal Melbourne Hospital, Parkville, Victoria, Australia; Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia; Genomic Medicine and Family Cancer Clinic, The Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Aung K Win
- Centre for Epidemiology and Biostatistics, The University of Melbourne, Parkville, Victoria, Australia
| | - John L Hopper
- Centre for Epidemiology and Biostatistics, The University of Melbourne, Parkville, Victoria, Australia
| | - Mark A Jenkins
- Centre for Epidemiology and Biostatistics, The University of Melbourne, Parkville, Victoria, Australia
| | - Ingrid M Winship
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Victoria, Australia; Genomic Medicine and Family Cancer Clinic, The Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Daniel D Buchanan
- Colorectal Oncogenomics Group, Department of Clinical Pathology, The University of Melbourne, Parkville, Victoria, Australia; Centre for Cancer Research, Victorian Comprehensive Cancer Centre, The University of Melbourne, Parkville, Victoria, Australia; Genomic Medicine and Family Cancer Clinic, The Royal Melbourne Hospital, Parkville, Victoria, Australia.
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11
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Morak M, Steinke-Lange V, Massdorf T, Benet-Pages A, Locher M, Laner A, Kayser K, Aretz S, Holinski-Feder E. Prevalence of CNV-neutral structural genomic rearrangements in MLH1, MSH2, and PMS2 not detectable in routine NGS diagnostics. Fam Cancer 2021; 19:161-167. [PMID: 32002723 DOI: 10.1007/s10689-020-00159-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Routine diagnostics for colorectal cancer patients suspected of having Lynch-Syndrome (LS) currently uses Next-Generation-Sequencing (NGS) of targeted regions within the DNA mismatch repair (MMR) genes. This analysis can reliably detect nucleotide alterations and copy-number variations (CNVs); however, CNV-neutral rearrangements comprising gene inversions or large intronic insertions remain undetected because their breakpoints are usually not covered. As several founder mutations exist for LS, we established PCR-based screening methods for five known rearrangements in MLH1, MSH2, or PMS2, and investigated their prevalence in 98 German patients with suspicion of LS without a causative germline variant or CNV detectable in the four MMR genes. We found no recurrence of CNV-neutral structural rearrangements previously described: Neither for two inversions in MLH1 (exon 1 and exon 16-19) within 33 MLH1-deficient patients, nor for two inversions in MSH2 (exon 1-7 and exon 2-6) within 48 MSH2-deficient patients. The PMS2 insertion in intron 7 was detected in one of 17 PMS2-deficient patients. None of the four genomic inversions constitutes a founder event within the German population, but we advise to test the rare cases with unsolved PMS2-deficiency upon the known insertion. As a next diagnostic step, tumour tissue of the unsolved patients should be sequenced for somatic variants, and germline analysis of additional genes with an overlapping clinical phenotype should be considered. Alternatively, full-length cDNA analyses may detect concealed MMR-defects in cases with family history.
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Affiliation(s)
- Monika Morak
- Medizinische Klinik Und Poliklinik IV, Campus Innenstadt, Klinikum Der Universität München, Ziemssenstr. 1, 80336, Munich, Germany. .,MGZ - Medizinisch Genetisches Zentrum, Bayerstr. 3-5, 80335, Munich, Germany.
| | - Verena Steinke-Lange
- Medizinische Klinik Und Poliklinik IV, Campus Innenstadt, Klinikum Der Universität München, Ziemssenstr. 1, 80336, Munich, Germany.,MGZ - Medizinisch Genetisches Zentrum, Bayerstr. 3-5, 80335, Munich, Germany
| | - Trisari Massdorf
- Medizinische Klinik Und Poliklinik IV, Campus Innenstadt, Klinikum Der Universität München, Ziemssenstr. 1, 80336, Munich, Germany.,MGZ - Medizinisch Genetisches Zentrum, Bayerstr. 3-5, 80335, Munich, Germany
| | - Anna Benet-Pages
- Medizinische Klinik Und Poliklinik IV, Campus Innenstadt, Klinikum Der Universität München, Ziemssenstr. 1, 80336, Munich, Germany
| | - Melanie Locher
- Medizinische Klinik Und Poliklinik IV, Campus Innenstadt, Klinikum Der Universität München, Ziemssenstr. 1, 80336, Munich, Germany
| | - Andreas Laner
- Medizinische Klinik Und Poliklinik IV, Campus Innenstadt, Klinikum Der Universität München, Ziemssenstr. 1, 80336, Munich, Germany
| | - Katrin Kayser
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - Stefan Aretz
- Institute of Human Genetics, University of Bonn, Bonn, Germany.,Center for Hereditary Tumour Syndromes, University Hospital Bonn, Bonn, Germany
| | - Elke Holinski-Feder
- Medizinische Klinik Und Poliklinik IV, Campus Innenstadt, Klinikum Der Universität München, Ziemssenstr. 1, 80336, Munich, Germany. .,MGZ - Medizinisch Genetisches Zentrum, Bayerstr. 3-5, 80335, Munich, Germany.
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12
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Diagnosis of Lynch Syndrome and Strategies to Distinguish Lynch-Related Tumors from Sporadic MSI/dMMR Tumors. Cancers (Basel) 2021; 13:cancers13030467. [PMID: 33530449 PMCID: PMC7865821 DOI: 10.3390/cancers13030467] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Microsatellite instability (MSI) is a hallmark of Lynch syndrome (LS)-related tumors but is not specific, as most of MSI/mismatch repair-deficient (dMMR) tumors are sporadic. Therefore, the identification of MSI/dMMR requires additional diagnostic tools to identify LS. In this review, we address the hallmarks of LS and present recent advances in diagnostic and screening strategies to identify LS patients. We also discuss the pitfalls associated with current strategies, which should be taken into account in order to improve the diagnosis of LS. Abstract Microsatellite instability (MSI) is a hallmark of Lynch syndrome (LS)-related tumors but is not specific to it, as approximately 80% of MSI/mismatch repair-deficient (dMMR) tumors are sporadic. Methods leading to the diagnosis of LS have considerably evolved in recent years and so have tumoral tests for LS screening and for the discrimination of LS-related to MSI-sporadic tumors. In this review, we address the hallmarks of LS, including the clinical, histopathological, and molecular features. We present recent advances in diagnostic and screening strategies to identify LS patients. We also discuss the pitfalls associated with the current strategies, which should be taken into account to improve the diagnosis of LS and avoid inappropriate clinical management.
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Oldfield LE, Li T, Tone A, Aronson M, Edwards M, Holter S, Quevedo R, Van de Laar E, Lerner-Ellis J, Pollett A, Clarke B, Tabori U, Gallinger S, Ferguson SE, Pugh TJ. An Integrative DNA Sequencing and Methylation Panel to Assess Mismatch Repair Deficiency. J Mol Diagn 2020; 23:242-252. [PMID: 33259954 DOI: 10.1016/j.jmoldx.2020.11.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 10/09/2020] [Accepted: 11/09/2020] [Indexed: 12/30/2022] Open
Abstract
Clinical testing for mismatch repair (MMR) deficiency often entails serial testing of tumor and constitutional DNA using multiple assays. To minimize cost and specimen requirements of MMR testing, we developed an integrated targeted sequencing protocol (termed MultiMMR) that tests for promoter methylation, mutations, copy number alterations, copy neutral loss of heterozygosity, and microsatellite instability from a single aliquot of DNA. Hybrid capture of DNA-sequencing libraries constructed with methylated adapters was performed on 142 samples (60 tumors and 82 constitutional samples) from 82 patients with MMR-associated colorectal, endometrial, and brain cancers as well as a synthetic DNA mix with 11 known mutations. The captured material was split to enable parallel bisulfite and conventional sequence analysis. The panel targeted microsatellite regions and 13 genes associated with MMR, hypermutation, and hereditary colorectal cancer. MultiMMR recapitulated clinical testing results in 23 of 24 cases, was able to explain MMR loss in an additional 29 of 48 patients with incomplete or inconclusive testing, and identified all 11 MMR variants within the synthetic DNA mix. Promoter methylation and microsatellite instability analysis found 95% and 97% concordance with clinical testing, respectively. We report the feasibility for amalgamation of the current stepwise and complex clinical testing workflow into an integrated test for hereditary and somatic causes of MMR deficiency.
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Affiliation(s)
- Leslie E Oldfield
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Tiantian Li
- Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Alicia Tone
- Division of Gynecologic Oncology, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Melyssa Aronson
- Zane Cohen Centre for Digestive Diseases, Mount Sinai Hospital, Toronto, Ontario, Canada
| | | | - Spring Holter
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Rene Quevedo
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
| | - Emily Van de Laar
- Division of Gynecologic Oncology, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Jordan Lerner-Ellis
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada; Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Aaron Pollett
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Blaise Clarke
- Laboratory Medicine Program, University Health Network, Toronto, Ontario, Canada
| | - Uri Tabori
- The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Steven Gallinger
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada; Ontario Institute for Cancer Research, Toronto, Ontario, Canada
| | - Sarah E Ferguson
- Division of Gynecologic Oncology, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Trevor J Pugh
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada; Ontario Institute for Cancer Research, Toronto, Ontario, Canada.
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Alvarez MEV, Chivers M, Borovska I, Monger S, Giannoulatou E, Kralovicova J, Vorechovsky I. Transposon clusters as substrates for aberrant splice-site activation. RNA Biol 2020; 18:354-367. [PMID: 32965162 PMCID: PMC7951965 DOI: 10.1080/15476286.2020.1805909] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Transposed elements (TEs) have dramatically shaped evolution of the exon-intron structure and significantly contributed to morbidity, but how recent TE invasions into older TEs cooperate in generating new coding sequences is poorly understood. Employing an updated repository of new exon-intron boundaries induced by pathogenic mutations, termed DBASS, here we identify novel TE clusters that facilitated exon selection. To explore the extent to which such TE exons maintain RNA secondary structure of their progenitors, we carried out structural studies with a composite exon that was derived from a long terminal repeat (LTR78) and AluJ and was activated by a C > T mutation optimizing the 5ʹ splice site. Using a combination of SHAPE, DMS and enzymatic probing, we show that the disease-causing mutation disrupted a conserved AluJ stem that evolved from helix 3.3 (or 5b) of 7SL RNA, liberating a primordial GC 5ʹ splice site from the paired conformation for interactions with the spliceosome. The mutation also reduced flexibility of conserved residues in adjacent exon-derived loops of the central Alu hairpin, revealing a cross-talk between traditional and auxilliary splicing motifs that evolved from opposite termini of 7SL RNA and were approximated by Watson-Crick base-pairing already in organisms without spliceosomal introns. We also identify existing Alu exons activated by the same RNA rearrangement. Collectively, these results provide valuable TE exon models for studying formation and kinetics of pre-mRNA building blocks required for splice-site selection and will be useful for fine-tuning auxilliary splicing motifs and exon and intron size constraints that govern aberrant splice-site activation.
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Affiliation(s)
| | - Martin Chivers
- School of Medicine, University of Southampton, Southampton, UK
| | - Ivana Borovska
- Slovak Academy of Sciences, Institute of Molecular Physiology and Genetics, Bratislava, Slovak Republic
| | - Steven Monger
- Computational Genomics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, Australia
| | - Eleni Giannoulatou
- Computational Genomics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, Australia.,St. Vincent's Clinical School, University of New South Wales, Sydney, Australia
| | - Jana Kralovicova
- School of Medicine, University of Southampton, Southampton, UK.,Slovak Academy of Sciences, Institute of Molecular Physiology and Genetics, Bratislava, Slovak Republic
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15
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Xu Y, Huang Z, Li C, Zhu C, Zhang Y, Guo T, Liu F, Xu Y. Comparison of Molecular, Clinicopathological, and Pedigree Differences Between Lynch-Like and Lynch Syndromes. Front Genet 2020; 11:991. [PMID: 32973888 PMCID: PMC7466573 DOI: 10.3389/fgene.2020.00991] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 08/05/2020] [Indexed: 12/12/2022] Open
Abstract
In this study, we compared the molecular, clinical, and pathological characteristics, as well as pedigrees, between patients with Lynch-like syndrome (LLS) and confirmed Lynch syndrome (LS) to develop appropriate management strategies for patients with LLS and their affected family members. Between June 2008 and September 2018, 81 patients with LLS and 47 patients with LS who developed colorectal cancer (CRC) were enrolled in this study. Multigene panel testing included 139 genes and was performed for all patients. The variants identified in each group were described, and clinicopathological characteristics and pedigrees were compared between the two groups. In the LLS group, a total of 52 variants were detected in 44 (54.3%) patients. Among the 52 variants, 17 were variants of unknown significance in mismatch repair genes, and the other most frequently mutated genes were MUYTH, POLE, BRCA2, and GJB2. The proportion of early-onset patients was significantly higher among the LS probands than among the LLS probands (74.5 and 53.1%, respectively; χ2 = 5.712, P = 0.017). On the other hand, the proportion of primary CRC developed in the rectum was higher in the LLS group than in the LS group (25.9 and 10.6%, respectively; χ2 = 2.358, P = 0.046). There were no significant differences in the occurrence of metachronous CRC (P = 0.632) and extra-colorectal cancer (extra-CRC) (P = 0.145) between the two groups. However, analysis of pedigrees showed that more patients developed CRC in the LS families (P = 0.013), whereas more patients with extra-CRC were observed in the LLS families (P = 0.045). A higher prevalence of male patients was observed in the LLS families (P = 0.036). In conclusion, LLS should be classified as a mixed entity, containing cases of LS, other hereditary cancer syndromes, and sporadic CRC. The high risks of CRC and extra-CRCs, which were found in this study, suggest tailored management policy and surveillance should be formulated based on individual and family risk. The surveillance regimen can be based on the presence of confirmed pathogenic/likely pathogenic germline variant(s) and family history.
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Affiliation(s)
- Yun Xu
- Department of Colorectal Surgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Zonghao Huang
- Hospital Information Centre, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Cong Li
- Department of Colorectal Surgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Congcong Zhu
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yuqin Zhang
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Tian'an Guo
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
| | - Fangqi Liu
- Department of Colorectal Surgery, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Ye Xu
- Department of Colorectal Surgery, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai, China
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16
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Canson D, Glubb D, Spurdle AB. Variant effect on splicing regulatory elements, branchpoint usage, and pseudoexonization: Strategies to enhance bioinformatic prediction using hereditary cancer genes as exemplars. Hum Mutat 2020; 41:1705-1721. [PMID: 32623769 DOI: 10.1002/humu.24074] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 06/26/2020] [Accepted: 07/02/2020] [Indexed: 12/15/2022]
Abstract
It is possible to estimate the prior probability of pathogenicity for germline disease gene variants based on bioinformatic prediction of variant effect/s. However, routinely used approaches have likely led to the underestimation and underreporting of variants located outside donor and acceptor splice site motifs that affect messenger RNA (mRNA) processing. This review presents information about hereditary cancer gene germline variants, outside native splice sites, with experimentally validated splicing effects. We list 95 exonic variants that impact splicing regulatory elements (SREs) in BRCA1, BRCA2, MLH1, MSH2, MSH6, and PMS2. We utilized a pre-existing large-scale BRCA1 functional data set to map functional SREs, and assess the relative performance of different tools to predict effects of 283 variants on such elements. We also describe rare examples of intronic variants that impact branchpoint (BP) sites and create pseudoexons. We discuss the challenges in predicting variant effect on BP site usage and pseudoexonization, and suggest strategies to improve the bioinformatic prioritization of such variants for experimental validation. Importantly, our review and analysis highlights the value of considering impact of variants outside donor and acceptor motifs on mRNA splicing and disease causation.
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Affiliation(s)
- Daffodil Canson
- Genetics and Computational Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Dylan Glubb
- Genetics and Computational Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Amanda B Spurdle
- Genetics and Computational Biology Department, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
- Faculty of Medicine, The University of Queensland, Brisbane, Queensland, Australia
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17
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Landrith T, Li B, Cass AA, Conner BR, LaDuca H, McKenna DB, Maxwell KN, Domchek S, Morman NA, Heinlen C, Wham D, Koptiuch C, Vagher J, Rivera R, Bunnell A, Patel G, Geurts JL, Depas MM, Gaonkar S, Pirzadeh-Miller S, Krukenberg R, Seidel M, Pilarski R, Farmer M, Pyrtel K, Milliron K, Lee J, Hoodfar E, Nathan D, Ganzak AC, Wu S, Vuong H, Xu D, Arulmoli A, Parra M, Hoang L, Molparia B, Fennessy M, Fox S, Charpentier S, Burdette J, Pesaran T, Profato J, Smith B, Haynes G, Dalton E, Crandall JRR, Baxter R, Lu HM, Tippin-Davis B, Elliott A, Chao E, Karam R. Splicing profile by capture RNA-seq identifies pathogenic germline variants in tumor suppressor genes. NPJ Precis Oncol 2020; 4:4. [PMID: 32133419 PMCID: PMC7039900 DOI: 10.1038/s41698-020-0109-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 01/30/2020] [Indexed: 12/12/2022] Open
Abstract
Germline variants in tumor suppressor genes (TSGs) can result in RNA mis-splicing and predisposition to cancer. However, identification of variants that impact splicing remains a challenge, contributing to a substantial proportion of patients with suspected hereditary cancer syndromes remaining without a molecular diagnosis. To address this, we used capture RNA-sequencing (RNA-seq) to generate a splicing profile of 18 TSGs (APC, ATM, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, MLH1, MSH2, MSH6, MUTYH, NF1, PALB2, PMS2, PTEN, RAD51C, RAD51D, and TP53) in 345 whole-blood samples from healthy donors. We subsequently demonstrated that this approach can detect mis-splicing by comparing splicing profiles from the control dataset to profiles generated from whole blood of individuals previously identified with pathogenic germline splicing variants in these genes. To assess the utility of our TSG splicing profile to prospectively identify pathogenic splicing variants, we performed concurrent capture DNA and RNA-seq in a cohort of 1000 patients with suspected hereditary cancer syndromes. This approach improved the diagnostic yield in this cohort, resulting in a 9.1% relative increase in the detection of pathogenic variants, demonstrating the utility of performing simultaneous DNA and RNA genetic testing in a clinical context.
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Affiliation(s)
| | - Bing Li
- Ambry Genetics, Aliso Viejo, CA USA
| | | | | | | | | | | | | | | | | | - Deborah Wham
- Aurora St. Luke’s Medical Center, Milwaukee, WI USA
| | | | | | - Ragene Rivera
- Texas Oncology, El Paso, Fort Worth, and Austin, TX USA
| | - Ann Bunnell
- Texas Oncology, El Paso, Fort Worth, and Austin, TX USA
| | - Gayle Patel
- Texas Oncology, El Paso, Fort Worth, and Austin, TX USA
| | | | | | | | | | | | | | - Robert Pilarski
- Ohio State University Wexner Medical Center and James Comprehensive Cancer Center, Columbus, OH USA
| | - Meagan Farmer
- University of Alabama at Birmingham, Birmingham, AL USA
| | | | | | - John Lee
- Cedars-Sinai Medical Center, Los Angeles, CA USA
| | | | | | | | - Sitao Wu
- Ambry Genetics, Aliso Viejo, CA USA
| | | | - Dong Xu
- Ambry Genetics, Aliso Viejo, CA USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Elizabeth Chao
- Ambry Genetics, Aliso Viejo, CA USA
- University of California at Irvine, Irvine, CA USA
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18
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Arnold AM, Morak M, Benet-Pagès A, Laner A, Frishman D, Holinski-Feder E. Targeted deep-intronic sequencing in a cohort of unexplained cases of suspected Lynch syndrome. Eur J Hum Genet 2019; 28:597-608. [PMID: 31822864 DOI: 10.1038/s41431-019-0536-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 12/28/2022] Open
Abstract
Lynch syndrome (LS) is caused by germline defects in DNA mismatch repair (MMR) pathway, resulting in microsatellite instability (MSI-H) and loss of immunohistochemical staining (IHC) of the respective protein in tumor tissue. However, not in all clinically suspected LS patients with MSI-H tumors and IHC-loss, causative germline alterations in the MMR genes can be detected. Here, we investigated 128 of these patients to possibly define new pathomechanisms. A search for large genomic rearrangements and deep-intronic regulatory variants was performed via targeted next-generation sequencing (NGS) of exonic, intronic, and chromosomal regions upstream and downstream of MLH1, MSH2, MSH6, PMS2, MLH3, MSH3, PMS1, and EPCAM. Within this cohort, two different large rearrangements causative for LS were detected in three cases, belonging to two families (2.3%). The sensitivity to detect large rearrangements or copy number variations (CNV) was evaluated to be 50%. In 9 of the 128 patients (7%), previously overlooked pathogenic single-nucleotide variants (SNV) and two variants of uncertain significance (VUS) were identified in MLH1, MSH2, and MSH6. Pathogenic aberrations were not found in MLH3, MSH3, and PMS1. A potential effect on regulation was exerted for 19% of deep-intronic SNVs, predominantly located in chromosomal regions where the modification of histone proteins suggests an enhancer function. In conclusion, conventional variation analysis of coding regions is missing rare genomic rearrangements, nevertheless they should be analyzed. Assessment of deep-intronic SNVs is so far non-conclusive for medical questioning.
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Affiliation(s)
- Anke Marie Arnold
- Medizinisch Genetisches Zentrum-MGZ, Munich, Germany.,Department of Bioinformatics, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany
| | - Monika Morak
- Medizinisch Genetisches Zentrum-MGZ, Munich, Germany.,Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Munich, Germany
| | | | - Andreas Laner
- Medizinisch Genetisches Zentrum-MGZ, Munich, Germany
| | - Dimitrij Frishman
- Department of Bioinformatics, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany.,Laboratory of Bioinformatics, RASA Research Center, St. Petersburg State Polytechnic University, St. Petersburg, Russia, 195251
| | - Elke Holinski-Feder
- Medizinisch Genetisches Zentrum-MGZ, Munich, Germany. .,Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Munich, Germany.
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19
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Jenkins MA, Win AK, Templeton AS, Angelakos MS, Buchanan DD, Cotterchio M, Figueiredo JC, Thibodeau SN, Baron JA, Potter JD, Hopper JL, Casey G, Gallinger S, Le Marchand L, Lindor NM, Newcomb PA, Haile RW. Cohort Profile: The Colon Cancer Family Registry Cohort (CCFRC). Int J Epidemiol 2018; 47:387-388i. [PMID: 29490034 PMCID: PMC5913593 DOI: 10.1093/ije/dyy006] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 12/19/2017] [Accepted: 01/15/2018] [Indexed: 01/02/2023] Open
Affiliation(s)
- Mark A Jenkins
- Centre for Epidemiology and Biostatistics, University of Melbourne, Parkville, VIC, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC, Australia
| | - Aung Ko Win
- Centre for Epidemiology and Biostatistics, University of Melbourne, Parkville, VIC, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC, Australia
- Genetic Medicine, Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Allyson S Templeton
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Maggie S Angelakos
- Centre for Epidemiology and Biostatistics, University of Melbourne, Parkville, VIC, Australia
| | - Daniel D Buchanan
- Centre for Epidemiology and Biostatistics, University of Melbourne, Parkville, VIC, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC, Australia
- Genetic Medicine, Royal Melbourne Hospital, Parkville, VIC, Australia
- Colorectal Oncogenomics Group, University of Melbourne, Parkville, VIC, Australia
| | | | - Jane C Figueiredo
- Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | | | - John A Baron
- Department of Medicine, University of North Carolina School of Medicine, and Department of Epidemiology, Gillings School of Global Public Health, Chapel Hill, NC, USA
| | - John D Potter
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- School of Public Health, University of Washington, Seattle, WA, USA
| | - John L Hopper
- Centre for Epidemiology and Biostatistics, University of Melbourne, Parkville, VIC, Australia
- University of Melbourne Centre for Cancer Research, Victorian Comprehensive Cancer Centre, Parkville, VIC, Australia
| | - Graham Casey
- Center for Public Health Genomics, University of Virginia, Charlottesville, VA, USA
| | - Steven Gallinger
- Lunenfeld Tanenbaum Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON, Canada
| | | | - Noralane M Lindor
- Department of Health Science Research, Mayo Clinic Arizona, Scottsdale, AZ, USA
| | - Polly A Newcomb
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
- School of Public Health, University of Washington, Seattle, WA, USA
| | - Robert W Haile
- Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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20
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Pseudoexons provide a mechanism for allele-specific expression of APC in familial adenomatous polyposis. Oncotarget 2018; 7:70685-70698. [PMID: 27683109 PMCID: PMC5342583 DOI: 10.18632/oncotarget.12206] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 09/12/2016] [Indexed: 12/11/2022] Open
Abstract
Allele-specific expression (ASE) of the Adenomatous Polyposis Coli (APC) gene occurs in up to one-third of families with adenomatous polyposis (FAP) that have screened mutation-negative by conventional techniques. To advance our understanding of the genomic basis of this phenomenon, 54 APC mutation-negative families (21 with classical FAP and 33 with attenuated FAP, AFAP) were investigated. We focused on four families with validated ASE and scrutinized these families by sequencing of the blood transcriptomes (RNA-seq) and genomes (WGS). Three families, two with classical FAP and one with AFAP, revealed deep intronic mutations associated with pseudoexons. In all three families, intronic mutations (c.646-1806T>G in intron 6, c.1408+729A>G in intron 11, and c.1408+731C>T in intron 11) created new splice donor sites resulting in the insertion of intronic sequences (of 127 bp, 83 bp, and 83 bp, respectively) in the APC transcript. The respective intronic mutations were absent in the remaining polyposis families and the general population. Premature stop of translation as the predicted consequence as well as co-segregation with polyposis supported the pathogenicity of the pseudoexons. We conclude that next generation sequencing on RNA and genomic DNA is an effective strategy to reveal and validate pseudoexons that are regularly missed by traditional screening methods and is worth considering in apparent mutation-negative polyposis families.
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Rath M, Jenssen SE, Schwefel K, Spiegler S, Kleimeier D, Sperling C, Kaderali L, Felbor U. High-throughput sequencing of the entire genomic regions of CCM1/KRIT1 , CCM2 and CCM3/PDCD10 to search for pathogenic deep-intronic splice mutations in cerebral cavernous malformations. Eur J Med Genet 2017. [DOI: 10.1016/j.ejmg.2017.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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22
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Vargas-Parra GM, González-Acosta M, Thompson BA, Gómez C, Fernández A, Dámaso E, Pons T, Morak M, Del Valle J, Iglesias S, Velasco À, Solanes A, Sanjuan X, Padilla N, de la Cruz X, Valencia A, Holinski-Feder E, Brunet J, Feliubadaló L, Lázaro C, Navarro M, Pineda M, Capellá G. Elucidating the molecular basis of MSH2-deficient tumors by combined germline and somatic analysis. Int J Cancer 2017; 141:1365-1380. [PMID: 28577310 DOI: 10.1002/ijc.30820] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 05/06/2017] [Accepted: 05/16/2017] [Indexed: 12/20/2022]
Abstract
In a proportion of patients presenting mismatch repair (MMR)-deficient tumors, no germline MMR mutations are identified, the so-called Lynch-like syndrome (LLS). Recently, MMR-deficient tumors have been associated with germline mutations in POLE and MUTYH or double somatic MMR events. Our aim was to elucidate the molecular basis of MSH2-deficient LS-suspected cases using a comprehensive analysis of colorectal cancer (CRC)-associated genes at germline and somatic level. Fifty-eight probands harboring MSH2-deficient tumors were included. Germline mutational analysis of MSH2 (including EPCAM deletions) and MSH6 was performed. Pathogenicity of MSH2 variants was assessed by RNA analysis and multifactorial likelihood calculations. MSH2 cDNA and methylation of MSH2 and MSH6 promoters were studied. Matched blood and tumor DNA were analyzed using a customized next generation sequencing panel. Thirty-five individuals were carriers of pathogenic or probably pathogenic variants in MSH2 and EPCAM. Five patients harbored 4 different MSH2 variants of unknown significance (VUS) and one had 2 novel MSH6 promoter VUS. Pathogenicity assessment allowed the reclassification of the 4 MSH2 VUS and 6 probably pathogenic variants as pathogenic mutations, enabling a total of 40 LS diagnostics. Predicted pathogenic germline variants in BUB1, SETD2, FAN1 and MUTYH were identified in 5 cases. Three patients had double somatic hits in MSH2 or MSH6, and another 2 had somatic alterations in other MMR genes and/or proofreading polymerases. In conclusion, our comprehensive strategy combining germline and somatic mutational status of CRC-associated genes by means of a subexome panel allows the elucidation of up to 86% of MSH2-deficient suspected LS tumors.
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Affiliation(s)
- Gardenia M Vargas-Parra
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, CIBERONC, Hospitalet de Llobregat, Spain
| | - Maribel González-Acosta
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, CIBERONC, Hospitalet de Llobregat, Spain
| | - Bryony A Thompson
- Huntsman Cancer Institute, University of Utah School of Medicine, Salt Lake City, UT.,Centre for Epidemiology and Biostatistics, School of Population and Global Health, University of Melbourne, Melbourne, Australia
| | - Carolina Gómez
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, CIBERONC, Hospitalet de Llobregat, Spain
| | - Anna Fernández
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, CIBERONC, Hospitalet de Llobregat, Spain
| | - Estela Dámaso
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, CIBERONC, Hospitalet de Llobregat, Spain
| | - Tirso Pons
- Structural Biology and Biocomputing Program, Spanish National Cancer Research Center (CNIO), Madrid, Spain
| | - Monika Morak
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. Germany MGZ-Medizinisch Genetisches Zentrum, Munich, Germany.,MGZ-Medizinisch Genetisches Zentrum, Munich, Germany
| | - Jesús Del Valle
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, CIBERONC, Hospitalet de Llobregat, Spain
| | - Silvia Iglesias
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, CIBERONC, Hospitalet de Llobregat, Spain
| | - Àngela Velasco
- Hereditary Cancer Program, Catalan Institute of Oncology, IdIBGI, Girona, Spain
| | - Ares Solanes
- Hereditary Cancer Program, Catalan Institute of Oncology, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Xavier Sanjuan
- Pathology Department, Hospital Universitari de Bellvitge-IDIBELL, Hospitalet de Llobregat, Barcelona, Spain
| | - Natàlia Padilla
- Research Unit in Translational Bioinformatics, Vall d'Hebron Research Institute (VHIR), Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
| | - Xavier de la Cruz
- Research Unit in Translational Bioinformatics, Vall d'Hebron Research Institute (VHIR), Universitat Autònoma de Barcelona (UAB), Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Alfonso Valencia
- Structural Biology and Biocomputing Program, Spanish National Cancer Research Center (CNIO), Madrid, Spain
| | - Elke Holinski-Feder
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. Germany MGZ-Medizinisch Genetisches Zentrum, Munich, Germany.,MGZ-Medizinisch Genetisches Zentrum, Munich, Germany
| | - Joan Brunet
- Hereditary Cancer Program, Catalan Institute of Oncology, IdIBGI, Girona, Spain
| | - Lídia Feliubadaló
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, CIBERONC, Hospitalet de Llobregat, Spain
| | - Conxi Lázaro
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, CIBERONC, Hospitalet de Llobregat, Spain
| | - Matilde Navarro
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, CIBERONC, Hospitalet de Llobregat, Spain.,Hereditary Cancer Program, Catalan Institute of Oncology, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Marta Pineda
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, CIBERONC, Hospitalet de Llobregat, Spain
| | - Gabriel Capellá
- Hereditary Cancer Program, Catalan Institute of Oncology, IDIBELL, CIBERONC, Hospitalet de Llobregat, Spain
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23
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Deep intronic mutations and human disease. Hum Genet 2017; 136:1093-1111. [DOI: 10.1007/s00439-017-1809-4] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 05/05/2017] [Indexed: 12/22/2022]
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24
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Villacis RAR, Abreu FB, Miranda PM, Domingues MAC, Carraro DM, Santos EMM, Andrade VP, Rossi BM, Achatz MI, Rogatto SR. ROBO1 deletion as a novel germline alteration in breast and colorectal cancer patients. Tumour Biol 2016; 37:3145-53. [PMID: 26427657 DOI: 10.1007/s13277-015-4145-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 09/23/2015] [Indexed: 01/22/2023] Open
Abstract
Despite one third of breast (BC) and colorectal cancer (CRC) cases having a hereditary component, only a small proportion can be explained by germline mutations. The aim of this study was to identify potential genomic alterations related to cancer predisposition. Copy number variations (CNVs) were interrogated in 113 unrelated cases fulfilling the criteria for hereditary BC/CRC and presenting non-pathogenic mutations in BRCA1, BRCA2, MLH1, MSH2, TP53, and CHEK2 genes. An identical germline deep intronic deletion of ROBO1 was identified in three index patients using two microarray platforms (Agilent 4x180K and Affymetrix CytoScan HD). The ROBO1 deletion was confirmed by quantitative PCR (qPCR). Six relatives were also evaluated by CytoScan HD Array. Genomic analysis confirmed a co-segregation of the ROBO1 deletion with the occurrence of cancer in two families. Direct sequencing revealed no pathogenic ROBO1 point mutations. Transcriptomic analysis (HTA 2.0, Affymetrix) in two breast carcinomas from a single patient revealed ROBO1 down-expression with no splicing events near the intronic deletion. Deeper in silico analysis showed several enhancer regions and a histone methylation mark in the deleted region. The ROBO1 deletion in a putative transcriptional regulatory region, its down-expression in tumor samples, and the results of the co-segregation analysis revealing the presence of the alteration in affected individuals suggest a pathogenic effect of the ROBO1 in cancer predisposition.
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Affiliation(s)
- Rolando A R Villacis
- International Research Center (CIPE), A.C. Camargo Cancer Center, Rua Taguá 440, São Paulo, CEP: 01508-010, SP, Brazil
| | - Francine B Abreu
- International Research Center (CIPE), A.C. Camargo Cancer Center, Rua Taguá 440, São Paulo, CEP: 01508-010, SP, Brazil
| | - Priscila M Miranda
- International Research Center (CIPE), A.C. Camargo Cancer Center, Rua Taguá 440, São Paulo, CEP: 01508-010, SP, Brazil
| | - Maria A C Domingues
- Department of Pathology, Faculty of Medicine, University of São Paulo State (UNESP), Botucatu, SP, Brazil
| | - Dirce M Carraro
- International Research Center (CIPE), A.C. Camargo Cancer Center, Rua Taguá 440, São Paulo, CEP: 01508-010, SP, Brazil
| | | | - Victor P Andrade
- Department of Pathology, A.C. Camargo Cancer Center, São Paulo, SP, Brazil
| | | | - Maria I Achatz
- Department of Oncogenetics, A.C. Camargo Cancer Center, São Paulo, SP, Brazil
| | - Silvia R Rogatto
- International Research Center (CIPE), A.C. Camargo Cancer Center, Rua Taguá 440, São Paulo, CEP: 01508-010, SP, Brazil.
- Department of Urology, Faculty of Medicine, University of São Paulo State (UNESP), CEP: 18618-970, Botucatu, SP, Brazil.
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25
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Copy number variants associated with 18p11.32, DCC and the promoter 1B region of APC in colorectal polyposis patients. Meta Gene 2015; 7:95-104. [PMID: 26909336 PMCID: PMC4733217 DOI: 10.1016/j.mgene.2015.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 12/16/2015] [Accepted: 12/21/2015] [Indexed: 01/05/2023] Open
Abstract
Familial Adenomatous Polyposis (FAP) is the second most common inherited predisposition to colorectal cancer (CRC) associated with the development of hundreds to thousands of adenomas in the colon and rectum. Mutations in APC are found in ~ 80% polyposis patients with FAP. In the remaining 20% no genetic diagnosis can be provided suggesting other genes or mechanisms that render APC inactive may be responsible. Copy number variants (CNVs) remain to be investigated in FAP and may account for disease in a proportion of polyposis patients. A cohort of 56 polyposis patients and 40 controls were screened for CNVs using the 2.7M microarray (Affymetrix) with data analysed using ChAS (Affymetrix). A total of 142 CNVs were identified unique to the polyposis cohort suggesting their involvement in CRC risk. We specifically identified CNVs in four unrelated polyposis patients among CRC susceptibility genes APC, DCC, MLH1 and CTNNB1 which are likely to have contributed to disease development in these patients. A recurrent deletion was observed at position 18p11.32 in 9% of the patients screened that was of particular interest. Further investigation is necessary to fully understand the role of these variants in CRC risk given the high prevalence among the patients screened.
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Key Words
- ALL, acute lymphoblastic leukaemia
- BH, Bengamini and Hochberg
- CHAS, Chromosome Analysis Suite
- CN, copy number
- CNV
- CNV, copy number variation
- COSMIC, Catalogue of Somatic Mutations in Cancer
- CRC, colorectal cancer
- Cancer
- DGV, Database of genomic variants
- DNA, deoxyribose nucleic acid
- FAP, familial adenomatous polyposis
- HMDD, human microRNA disease database
- KEGG, Kyoto Encyclopaedia of Genes and Genomes
- Kb, kilobase
- LOH, loss of heterozygosity
- MLPA, multiplex ligation-dependant probe amplification
- MMR, mismatch repair
- NTC, no template control
- QC, quality control
- RNA, ribose nucleic acid
- SNP, single nucleotide polymorphism
- TAM, Tool for the annotation of microRNAs
- TCGA, The Cancer Genome Atlas
- UCSC, University of California, Santa Cruz
- diagnostic testing
- lncRNA, link RNA
- long non-coding RNAs
- mapd, median absolute pairwise difference
- miR, microRNA
- ng, nanogram
- polyposis
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26
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van der Klift HM, Jansen AML, van der Steenstraten N, Bik EC, Tops CMJ, Devilee P, Wijnen JT. Splicing analysis for exonic and intronic mismatch repair gene variants associated with Lynch syndrome confirms high concordance between minigene assays and patient RNA analyses. Mol Genet Genomic Med 2015; 3:327-45. [PMID: 26247049 PMCID: PMC4521968 DOI: 10.1002/mgg3.145] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 03/05/2015] [Accepted: 03/16/2015] [Indexed: 12/13/2022] Open
Abstract
A subset of DNA variants causes genetic disease through aberrant splicing. Experimental splicing assays, either RT-PCR analyses of patient RNA or functional splicing reporter minigene assays, are required to evaluate the molecular nature of the splice defect. Here, we present minigene assays performed for 17 variants in the consensus splice site regions, 14 exonic variants outside these regions, and two deep intronic variants, all in the DNA mismatch-repair (MMR) genes MLH1, MSH2, MSH6, and PMS2, associated with Lynch syndrome. We also included two deep intronic variants in APC and PKD2. For one variant (MLH1 c.122A>G), our minigene assay and patient RNA analysis could not confirm the previously reported aberrant splicing. The aim of our study was to further investigate the concordance between minigene splicing assays and patient RNA analyses. For 30 variants results from patient RNA analyses were available, either performed by our laboratory or presented in literature. Some variants were deliberately included in this study because they resulted in multiple aberrant transcripts in patient RNA analysis, or caused a splice effect other than the prevalent exon skip. While both methods were completely concordant in the assessment of splice effects, four variants exhibited major differences in aberrant splice patterns. Based on the present and earlier studies, together showing an almost 100% concordance of minigene assays with patient RNA analyses, we discuss the weight given to minigene splicing assays in the current criteria proposed by InSiGHT for clinical classification of MMR variants.
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Affiliation(s)
- Heleen M van der Klift
- Department of Human Genetics, Leiden University Medical Center Leiden, The Netherlands ; Department of Clinical Genetics, Leiden University Medical Center Leiden, The Netherlands
| | - Anne M L Jansen
- Department of Human Genetics, Leiden University Medical Center Leiden, The Netherlands
| | | | - Elsa C Bik
- Department of Clinical Genetics, Leiden University Medical Center Leiden, The Netherlands
| | - Carli M J Tops
- Department of Clinical Genetics, Leiden University Medical Center Leiden, The Netherlands
| | - Peter Devilee
- Department of Human Genetics, Leiden University Medical Center Leiden, The Netherlands ; Department of Pathology, Leiden University Medical Center Leiden, The Netherlands
| | - Juul T Wijnen
- Department of Human Genetics, Leiden University Medical Center Leiden, The Netherlands ; Department of Clinical Genetics, Leiden University Medical Center Leiden, The Netherlands
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27
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Win AK, Buchanan AD, Rosty C, MacInnis RJ, Dowty JG, Dite GS, Giles GG, Southey MC, Young JP, Clendenning M, Walsh MD, Walters RJ, Boussioutas A, Smyrk TC, Thibodeau SN, Baron JA, Potter JD, Newcomb PA, Marchand LL, Haile RW, Gallinger S, Lindor NM, Hopper JL, Ahnen DJ, Jenkins MA. Role of tumour molecular and pathology features to estimate colorectal cancer risk for first-degree relatives. Gut 2015; 64:101-10. [PMID: 24615377 PMCID: PMC4180004 DOI: 10.1136/gutjnl-2013-306567] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
OBJECTIVE To estimate risk of colorectal cancer (CRC) for first-degree relatives of CRC cases based on CRC molecular subtypes and tumour pathology features. DESIGN We studied a cohort of 33,496 first-degree relatives of 4853 incident invasive CRC cases (probands) who were recruited to the Colon Cancer Family Registry through population cancer registries in the USA, Canada and Australia. We categorised the first-degree relatives into four groups: 28,156 of 4095 mismatch repair (MMR)-proficient probands, 2302 of 301 MMR-deficient non-Lynch syndrome probands, 1799 of 271 suspected Lynch syndrome probands and 1239 of 186 Lynch syndrome probands. We compared CRC risk for first-degree relatives stratified by the absence or presence of specific tumour molecular pathology features in probands across each of these four groups and for all groups combined. RESULTS Compared with first-degree relatives of MMR-proficient CRC cases, a higher risk of CRC was estimated for first-degree relatives of CRC cases with suspected Lynch syndrome (HR 2.06, 95% CI 1.59 to 2.67) and with Lynch syndrome (HR 5.37, 95% CI 4.16 to 6.94), but not with MMR-deficient non-Lynch syndrome (HR 1.04, 95% CI 0.82 to 1.31). A greater risk of CRC was estimated for first-degree relatives if CRC cases were diagnosed before age 50 years, had proximal colon cancer or if their tumours had any of the following: expanding tumour margin, peritumoral lymphocytes, tumour-infiltrating lymphocytes or synchronous CRC. CONCLUSIONS Molecular pathology features are potentially useful to refine screening recommendations for first-degree relatives of CRC cases and to identify which cases are more likely to be caused by genetic or other familial factors.
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Affiliation(s)
- Aung Ko Win
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
| | - aniel D. Buchanan
- Cancer and Population Studies Group, Queensland Institute of Medical Research, Clive Berghofer Cancer Research Centre, Herston, Queensland, Australia
| | - Christophe Rosty
- Cancer and Population Studies Group, Queensland Institute of Medical Research, Clive Berghofer Cancer Research Centre, Herston, Queensland, Australia.,Department of Molecular and Cellular Pathology, University of Queensland, Herston, Queensland, Australia.,Envoi Specialist Pathologists, Herston, Queensland, Australia
| | - Robert J. MacInnis
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia.,Cancer Epidemiology Centre, Cancer Council Victoria, Carlton, Victoria, Australia
| | - James G. Dowty
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Gillian S. Dite
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Graham G. Giles
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia.,Cancer Epidemiology Centre, Cancer Council Victoria, Carlton, Victoria, Australia
| | - Melissa C. Southey
- Genetic Epidemiology Laboratory, Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia
| | - Joanne P. Young
- Cancer and Population Studies Group, Queensland Institute of Medical Research, Clive Berghofer Cancer Research Centre, Herston, Queensland, Australia
| | - Mark Clendenning
- Cancer and Population Studies Group, Queensland Institute of Medical Research, Clive Berghofer Cancer Research Centre, Herston, Queensland, Australia
| | - Michael D. Walsh
- Cancer and Population Studies Group, Queensland Institute of Medical Research, Clive Berghofer Cancer Research Centre, Herston, Queensland, Australia
| | - Rhiannon J. Walters
- Cancer and Population Studies Group, Queensland Institute of Medical Research, Clive Berghofer Cancer Research Centre, Herston, Queensland, Australia
| | - Alex Boussioutas
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia.,Cancer Genomics and Predictive Medicine, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia.,Sir Peter MacCallum Department of Oncology, The University of Melbourne, Parkville, Victoria, Australia
| | - Thomas C. Smyrk
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - Stephen N. Thibodeau
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA
| | - John A. Baron
- Department of Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - John D. Potter
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.,School of Public Health, University of Washington, Seattle, Washington, USA.,Centre for Public Health Research, Massey University, Wellington, New Zealand
| | - Polly A. Newcomb
- Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA.,School of Public Health, University of Washington, Seattle, Washington, USA
| | | | - Robert W. Haile
- Stanford Cancer Institute, Stanford University, San Francisco, California, USA
| | - Steven Gallinger
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.,Cancer Care Ontario, Toronto, Ontario, Canada
| | - Noralane M. Lindor
- Department of Health Science Research, Mayo Clinic Arizona, Scottsdale, Arizona, USA
| | - John L. Hopper
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Dennis J. Ahnen
- Department of Veterans Affairs, Eastern Colorado Health Care System, University of Colorado School of Medicine, Denver, Colorado, USA
| | - Mark A. Jenkins
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
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28
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Buchanan DD, Rosty C, Clendenning M, Spurdle AB, Win AK. Clinical problems of colorectal cancer and endometrial cancer cases with unknown cause of tumor mismatch repair deficiency (suspected Lynch syndrome). APPLICATION OF CLINICAL GENETICS 2014; 7:183-93. [PMID: 25328415 PMCID: PMC4199650 DOI: 10.2147/tacg.s48625] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Carriers of a germline mutation in one of the DNA mismatch repair (MMR) genes have a high risk of developing numerous different cancers, predominantly colorectal cancer and endometrial cancer (known as Lynch syndrome). MMR gene mutation carriers develop tumors with MMR deficiency identified by tumor microsatellite instability or immunohistochemical loss of MMR protein expression. Tumor MMR deficiency is used to identify individuals most likely to carry an MMR gene mutation. However, MMR deficiency can also result from somatic inactivation, most commonly methylation of the MLH1 gene promoter. As tumor MMR testing of all incident colorectal and endometrial cancers (universal screening) is becoming increasingly adopted, a growing clinical problem is emerging for individuals who have tumors that show MMR deficiency who are subsequently found not to carry an MMR gene mutation after genetic testing using the current diagnostic approaches (Sanger sequencing and multiplex ligation-dependent probe amplification) and who also show no evidence of MLH1 methylation. The inability to determine the underlying cause of tumor MMR deficiency in these “Lynch-like” or “suspected Lynch syndrome” cases has significant implications on the clinical management of these individuals and their relatives. When the data from published studies are combined, 59% (95% confidence interval [CI]: 55% to 64%) of colorectal cancers and 52% (95% CI: 41% to 62%) of endometrial cancers with MMR deficiency were identified as suspected Lynch syndrome. Recent studies estimated that colorectal cancer risk for relatives of suspected Lynch syndrome cases is lower than for relatives of those with MMR gene mutations, but higher than for relatives of those with tumor MMR deficiency resulting from methylation of the MLH1 gene promoter. The cause of tumor MMR deficiency in suspected Lynch syndrome cases is likely due to either unidentified germline MMR gene mutations, somatic cell mosaicism, or biallelic somatic inactivation. Determining the underlying cause of tumor MMR deficiency in suspected Lynch syndrome cases is likely to reshape the current triaging schemes used to identify germline MMR gene mutations in cancer-affected individuals and their relatives.
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Affiliation(s)
- Daniel D Buchanan
- Oncogenomics Group, Genetic Epidemiology Laboratory, Department of Pathology, The University of Melbourne, Parkville, VIC, Australia ; Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, VIC, Australia
| | - Christophe Rosty
- Oncogenomics Group, Genetic Epidemiology Laboratory, Department of Pathology, The University of Melbourne, Parkville, VIC, Australia ; Envoi Specialist Pathologists, Herston, QLD, Australia ; School of Medicine, University of Queensland, Herston, QLD, Australia
| | - Mark Clendenning
- Oncogenomics Group, Genetic Epidemiology Laboratory, Department of Pathology, The University of Melbourne, Parkville, VIC, Australia
| | - Amanda B Spurdle
- Molecular Cancer Epidemiology Laboratory, Genetics and Computational Biology Division, QIMR Berghofer Medical Research Institute, Herston, QLD, Australia
| | - Aung Ko Win
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, VIC, Australia
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29
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Newton K, Jorgensen NM, Wallace AJ, Buchanan DD, Lalloo F, McMahon RFT, Hill J, Evans DG. Tumour MLH1 promoter region methylation testing is an effective prescreen for Lynch Syndrome (HNPCC). J Med Genet 2014; 51:789-96. [PMID: 25280751 DOI: 10.1136/jmedgenet-2014-102552] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND AIMS Lynch syndrome (LS) patients have DNA mismatch repair deficiency and up to 80% lifetime risk of colorectal cancer (CRC). Screening of mutation carriers reduces CRC incidence and mortality. Selection for constitutional mutation testing relies on family history (Amsterdam and Bethesda Guidelines) and tumour-derived biomarkers. Initial biomarker analysis uses mismatch repair protein immunohistochemistry and microsatellite instability. Abnormalities in either identify mismatch repair deficiency but do not differentiate sporadic epigenetic defects, due to MLH1 promoter region methylation (13% of CRCs) from LS (4% of CRCs). A diagnostic biomarker capable of making this distinction would be valuable. This study compared two biomarkers in tumours with mismatch repair deficiency; quantification of methylation of the MLH1 promoter region using a novel assay and BRAF c.1799T>A, p.(Val600Glu) mutation status in the identification of constitutional mutations. METHODS Tumour DNA was extracted (formalin fixed, paraffin embedded, FFPE tissue) and pyrosequencing used to test for MLH1 promoter methylation and presence of the BRAF c.1799T>A, p.(Val600Glu) mutation 71 CRCs from individuals with pathogenic MLH1 mutations and 73 CRCs with sporadic MLH1 loss. Specificity and sensitivity was compared. FINDINGSS Unmethylated MLH1 promoter: sensitivity 94.4% (95% CI 86.2% to 98.4%), specificity 87.7% (95% CI 77.9% to 94.2%), Wild-type BRAF (codon 600): sensitivity 65.8% (95% CI 53.7% to 76.5%), specificity 98.6% (95% CI 92.4% to 100.0%) for the identification of those with pathogenic MLH1 mutations. CONCLUSIONS Quantitative MLH1 promoter region methylation using pyrosequencing is superior to BRAF codon 600 mutation status in identifying constitutional mutations in mismatch repair deficient tumours.
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Affiliation(s)
- K Newton
- Department of General Surgery, Manchester Royal Infirmary, Central Manchester University Hospitals NHS Trust, Manchester, UK
| | - N M Jorgensen
- Genomic Diagnostics Laboratory, Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Saint Mary's Hospital, Manchester, UK
| | - A J Wallace
- Genomic Diagnostics Laboratory, Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Saint Mary's Hospital, Manchester, UK
| | - D D Buchanan
- Cancer and Population Studies Group, Queensland Institute of Medical Research, Herston, Queensland, Australia Oncogenomics Group, Genetic Epidemiology Laboratory, Department of Pathology, The University of Melbourne, Parkville, Victoria, Australia Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
| | - F Lalloo
- Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Saint Mary's Hospital, Manchester, UK
| | - R F T McMahon
- Department of Histopathology, Manchester Royal Infirmary, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK Manchester Medical School, University of Manchester, Manchester, UK
| | - J Hill
- Department of General Surgery, Manchester Royal Infirmary, Central Manchester University Hospitals NHS Trust, Manchester, UK
| | - D G Evans
- Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Saint Mary's Hospital, Manchester, UK
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30
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Masson AL, Talseth-Palmer BA, Evans TJ, Grice DM, Hannan GN, Scott RJ. Expanding the genetic basis of copy number variation in familial breast cancer. Hered Cancer Clin Pract 2014; 12:15. [PMID: 24955146 PMCID: PMC4064283 DOI: 10.1186/1897-4287-12-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Accepted: 05/14/2014] [Indexed: 12/13/2022] Open
Abstract
Introduction Familial breast cancer (fBC) is generally associated with an early age of diagnosis and a higher frequency of disease among family members. Over the past two decades a number of genes have been identified that are unequivocally associated with breast cancer (BC) risk but there remain a significant proportion of families that cannot be accounted for by these genes. Copy number variants (CNVs) are a form of genetic variation yet to be fully explored for their contribution to fBC. CNVs exert their effects by either being associated with whole or partial gene deletions or duplications and by interrupting epigenetic patterning thereby contributing to disease development. CNV analysis can also be used to identify new genes and loci which may be associated with disease risk. Methods The Affymetrix Cytogenetic Whole Genome 2.7 M (Cyto2.7 M) arrays were used to detect regions of genomic re-arrangement in a cohort of 129 fBC BRCA1/BRCA2 mutation negative patients with a young age of diagnosis (<50 years) compared to 40 unaffected healthy controls (>55 years of age). Results CNV analysis revealed the presence of 275 unique rearrangements that were not present in the control population suggestive of their involvement in BC risk. Several CNVs were found that have been previously reported as BC susceptibility genes. This included CNVs in RPA3, NBN (NBS1), MRE11A and CYP19A1 in five unrelated fBC patients suggesting that these genes are involved in BC initiation and/or progression. Of special interest was the identification of WWOX and FHIT rearrangements in three unrelated fBC patients. Conclusions This study has identified a number of CNVs that potentially contribute to BC initiation and/or progression. The identification of CNVs that are associated with known tumour suppressor genes is of special interest that warrants further larger studies to understand their precise role in fBC.
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Affiliation(s)
- Amy L Masson
- Information Based Medicine Program, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW 2305, Australia ; School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle, Newcastle, NSW 2308, Australia
| | - Bente A Talseth-Palmer
- Information Based Medicine Program, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW 2305, Australia ; School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle, Newcastle, NSW 2308, Australia
| | - Tiffany-Jane Evans
- Information Based Medicine Program, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW 2305, Australia ; School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle, Newcastle, NSW 2308, Australia
| | - Desma M Grice
- Information Based Medicine Program, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW 2305, Australia ; CSIRO Preventative Health Flagship and Animal, CSIRO Food and Health Sciences Division, North Ryde, NSW 2113, Australia
| | - Garry N Hannan
- CSIRO Preventative Health Flagship and Animal, CSIRO Food and Health Sciences Division, North Ryde, NSW 2113, Australia
| | - Rodney J Scott
- Information Based Medicine Program, Hunter Medical Research Institute, University of Newcastle, Newcastle, NSW 2305, Australia ; Division of Molecular Medicine, Hunter Area Pathology Service, John Hunter Hospital, Newcastle, NSW 2305, Australia ; School of Biomedical Sciences and Pharmacy, Faculty of Health, University of Newcastle, Newcastle, NSW 2308, Australia
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Clendenning M, Walsh MD, Gelpi JB, Thibodeau SN, Lindor N, Potter JD, Newcomb P, LeMarchand L, Haile R, Gallinger S, Hopper JL, Jenkins MA, Rosty C, Young JP, Buchanan DD. Detection of large scale 3' deletions in the PMS2 gene amongst Colon-CFR participants: have we been missing anything? Fam Cancer 2014; 12:563-6. [PMID: 23288611 DOI: 10.1007/s10689-012-9597-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Current screening practices have been able to identify PMS2 mutations in 78 % of cases of colorectal cancer from the Colorectal Cancer Family Registry (Colon CFR) which showed solitary loss of the PMS2 protein. However the detection of large-scale deletions in the 3' end of the PMS2 gene has not been possible due to technical difficulties associated with pseudogene sequences. Here, we utilised a recently described MLPA/long-range PCR-based approach to screen the remaining 22 % (n = 16) of CRC-affected probands for mutations in the 3' end of the PMS2 gene. No deletions encompassing any or all of exons 12 through 15 were identified; therefore, our results suggest that 3' deletions in PMS2 are not a frequent occurrence in such families.
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Affiliation(s)
- Mark Clendenning
- Cancer and Population Studies, Queensland Institute of Medical Research, 300 Herston Road, Herston, QLD, 4006, Australia,
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Buchanan DD, Tan YY, Walsh MD, Clendenning M, Metcalf AM, Ferguson K, Arnold ST, Thompson BA, Lose FA, Parsons MT, Walters RJ, Pearson SA, Cummings M, Oehler MK, Blomfield PB, Quinn MA, Kirk JA, Stewart CJ, Obermair A, Young JP, Webb PM, Spurdle AB. Tumor mismatch repair immunohistochemistry and DNA MLH1 methylation testing of patients with endometrial cancer diagnosed at age younger than 60 years optimizes triage for population-level germline mismatch repair gene mutation testing. J Clin Oncol 2013; 32:90-100. [PMID: 24323032 DOI: 10.1200/jco.2013.51.2129] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PURPOSE Clinicopathologic data from a population-based endometrial cancer cohort, unselected for age or family history, were analyzed to determine the optimal scheme for identification of patients with germline mismatch repair (MMR) gene mutations. PATIENTS AND METHODS Endometrial cancers from 702 patients recruited into the Australian National Endometrial Cancer Study (ANECS) were tested for MMR protein expression using immunohistochemistry (IHC) and for MLH1 gene promoter methylation in MLH1-deficient cases. MMR mutation testing was performed on germline DNA of patients with MMR-protein deficient tumors. Prediction of germline mutation status was compared for combinations of tumor characteristics, age at diagnosis, and various clinical criteria (Amsterdam, Bethesda, Society of Gynecologic Oncology, ANECS). RESULTS Tumor MMR-protein deficiency was detected in 170 (24%) of 702 cases. Germline testing of 158 MMR-deficient cases identified 22 truncating mutations (3% of all cases) and four unclassified variants. Tumor MLH1 methylation was detected in 99 (89%) of 111 cases demonstrating MLH1/PMS2 IHC loss; all were germline MLH1 mutation negative. A combination of MMR IHC plus MLH1 methylation testing in women younger than 60 years of age at diagnosis provided the highest positive predictive value for the identification of mutation carriers at 46% versus ≤ 41% for any other criteria considered. CONCLUSION Population-level identification of patients with MMR mutation-positive endometrial cancer is optimized by stepwise testing for tumor MMR IHC loss in patients younger than 60 years, tumor MLH1 methylation in individuals with MLH1 IHC loss, and germline mutations in patients exhibiting loss of MSH6, MSH2, or PMS2 or loss of MLH1/PMS2 with absence of MLH1 methylation.
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Affiliation(s)
- Daniel D Buchanan
- Daniel D. Buchanan, Yen Y. Tan, Michael D. Walsh, Mark Clendenning, Alexander M. Metcalf, Kaltin Ferguson, Sven T. Arnold, Bryony A. Thompson, Felicity A. Lose, Michael T. Parsons, Rhiannon J. Walters, Sally-Ann Pearson, Joanne P. Young, Penelope M. Webb, and Amanda B. Spurdle, QIMR Berghofer Medical Research Institute, Herston; Yen Y. Tan and Andreas Obermair, University of Queensland School of Medicine, Brisbane; Margaret Cummings, University of Queensland Centre for Clinical Research, Herston, Queensland; Martin K. Oehler, Royal Adelaide Hospital, Adelaide, South Australia; Michael A. Quinn, Royal Women's Hospital, Melbourne, Victoria; Judy A. Kirk, Westmead Institute for Cancer Research, Westmead Millennium Institute, University of Sydney, Sydney, New South Wales; Colin J. Stewart, King Edward Memorial Hospital, Perth, Western Australia, Australia; and Penelope B. Blomfield, Royal Hobart Hospital, Hobart, Tasmania
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Role of pseudoexons and pseudointrons in human cancer. Int J Cell Biol 2013; 2013:810572. [PMID: 24204383 PMCID: PMC3800588 DOI: 10.1155/2013/810572] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 08/09/2013] [Indexed: 11/18/2022] Open
Abstract
In all eukaryotic organisms, pre-mRNA splicing and alternative splicing processes play an essential role in regulating the flow of information required to drive complex developmental and metabolic pathways. As a result, eukaryotic cells have developed a very efficient macromolecular machinery, called the spliceosome, to correctly recognize the pre-mRNA sequences that need to be inserted in a mature mRNA (exons) from those that should be removed (introns). In healthy individuals, alternative and constitutive splicing processes function with a high degree of precision and fidelity in order to ensure the correct working of this machinery. In recent years, however, medical research has shown that alterations at the splicing level play an increasingly important role in many human hereditary diseases, neurodegenerative processes, and especially in cancer origin and progression. In this minireview, we will focus on several genes whose association with cancer has been well established in previous studies, such as ATM, BRCA1/A2, and NF1. In particular, our objective will be to provide an overview of the known mechanisms underlying activation/repression of pseudoexons and pseudointrons; the possible utilization of these events as biomarkers of tumor staging/grading; and finally, the treatment options for reversing pathologic splicing events.
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Clendenning M, Young JP, Walsh MD, Woodall S, Arnold J, Jenkins M, Win AK, Hopper JL, Sweet K, Gallinger S, Rosty C, Parry S, Buchanan DD. Germline Mutations in the Polyposis-Associated Genes BMPR1A, SMAD4, PTEN, MUTYH and GREM1 Are Not Common in Individuals with Serrated Polyposis Syndrome. PLoS One 2013; 8:e66705. [PMID: 23805267 PMCID: PMC3689730 DOI: 10.1371/journal.pone.0066705] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Accepted: 05/08/2013] [Indexed: 12/28/2022] Open
Abstract
Background Recent reports have observed that individuals with serrated polyps, some of whom meet the clinical diagnostic criteria for Serrated Polyposis Syndrome (SPS), are among those who carry germline mutations in genes associated with polyposis syndromes including; (1) genes known to underlie hamartomatous polyposes (SMAD4, BMPR1A, and PTEN), (2) MUTYH-associated polyposis and (3) GREM1 in Hereditary Mixed Polyposis Syndrome (HMPS). The aim of this study was to characterise individuals fulfilling the current WHO criteria for SPS for germline mutations in these polyposis-associated genes. Methods A total of 65 individuals with SPS (fulfilling WHO criteria 1 or 3), were recruited to the Genetics of Serrated Neoplasia study between 2000 and 2012, through multiple Genetics or Family Cancer Clinics within Australia, or from the New Zealand Familial Gastrointestinal Cancer Service. Individuals with SPS were tested for coding mutations and large deletions in the PTEN, SMAD4, and BMPR1A genes, for the MUTYH variants in exons 7 (Y179C) and 13 (G396D), and for the duplication upstream of GREM1. Results We found no variants that were likely to be deleterious germline mutations in the SPS cases in the PTEN, SMAD4, and BMPR1A genes. A novel variant in intron 2 (c.164+223T>C) of PTEN was identified in one individual and was predicted by in silico analysis to have no functional consequences. One further individual with SPS was found to be mono-allelic for the MUTYH G396D mutation. No individuals carried the recently reported duplication within GREM1. Conclusions Genes involved in the gastrointestinal hamartomatous polyposis, Hereditary Mixed Polyposis Syndrome and MUTYH-associated polyposis syndromes are not commonly altered in individuals with SPS.
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Affiliation(s)
- Mark Clendenning
- Cancer and Population Studies Group, Queensland Institute of Medical Research, Brisbane, Queensland, Australia
| | - Joanne P. Young
- Cancer and Population Studies Group, Queensland Institute of Medical Research, Brisbane, Queensland, Australia
| | - Michael D. Walsh
- Cancer and Population Studies Group, Queensland Institute of Medical Research, Brisbane, Queensland, Australia
- Department of Histopathology, Sullivan Nicolaides Pathology, Brisbane, Queensland, Australia
| | - Sonja Woodall
- New Zealand Familial Gastrointestinal Cancer Service, Auckland Hospital, Auckland, New Zealand
| | - Julie Arnold
- New Zealand Familial Gastrointestinal Cancer Service, Auckland Hospital, Auckland, New Zealand
| | - Mark Jenkins
- Centre for MEGA Epidemiology, University of Melbourne, Melbourne, Victoria, Australia
| | - Aung Ko Win
- Centre for MEGA Epidemiology, University of Melbourne, Melbourne, Victoria, Australia
| | - John L. Hopper
- Centre for MEGA Epidemiology, University of Melbourne, Melbourne, Victoria, Australia
| | - Kevin Sweet
- Division of Human Genetics, The Ohio State University Medical Centre, Columbus, Ohio, United States of America
| | - Steven Gallinger
- Cancer Care Ontario, Toronto, Ontario, Canada
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
- Zane Cohen Centre for Digestive Diseases, Mount Sinai Hospital, Toronto, Ontario, Canada
| | - Christophe Rosty
- Cancer and Population Studies Group, Queensland Institute of Medical Research, Brisbane, Queensland, Australia
- Department of Molecular and Cellular Pathology, University of Queensland, Brisbane, Queensland, Australia
- Envoi Specialist Pathologists, Brisbane, Queensland, Australia
| | - Susan Parry
- New Zealand Familial Gastrointestinal Cancer Service, Auckland Hospital, Auckland, New Zealand
- Department of Gastroenterology and Hepatology, Middlemore Hospital, Auckland, New Zealand
| | - Daniel D. Buchanan
- Cancer and Population Studies Group, Queensland Institute of Medical Research, Brisbane, Queensland, Australia
- * E-mail:
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Clendenning M, Macrae FA, Walsh MD, Walters RJ, Thibodeau SN, Gunawardena SR, Potter JD, Haile RW, Gallinger S, Hopper JL, Jenkins MA, Rosty C, Young JP, Buchanan DD. Absence of PMS2 mutations in colon-CFR participants whose colorectal cancers demonstrate unexplained loss of MLH1 expression. Clin Genet 2012; 83:591-3. [PMID: 23017166 DOI: 10.1111/cge.12011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 08/05/2012] [Accepted: 08/31/2012] [Indexed: 11/29/2022]
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Veruttipong D, Soliman AS, Gilbert SF, Blachley TS, Hablas A, Ramadan M, Rozek LS, Seifeldin IA. Age distribution, polyps and rectal cancer in the Egyptian population-based cancer registry. World J Gastroenterol 2012; 18:3997-4003. [PMID: 22912550 PMCID: PMC3419996 DOI: 10.3748/wjg.v18.i30.3997] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 03/23/2012] [Accepted: 04/12/2012] [Indexed: 02/06/2023] Open
Abstract
AIM: To describe the clinical and epidemiologic profiles of the disease and to compare the findings with those generated from the previous hospital-based studies.
METHODS: The Gharbiah cancer registry is the only population-based cancer registry in Egypt since 1998. We analyzed the data of all colorectal cancer patients included in the registry for the period of 1999-2007. All medical records of the 1364 patients diagnosed in Gharbiah during the study period were retrieved and the following information abstracted: age, residence, diagnosis date, grade, stage, topology, clinical characteristics, and histology variables. Egyptian census data for 1996 and 2006 were used to provide the general population’s statistics on age, sex, residence and other related demographic factors. In addition to age- and sex-specific incidence rate analyses, we analyze the data to explore the incidence distribution by rural-urban differences among the 8 districts of the province. We also compared the incidence rates of Gharbiah to the rates of the Surveillance Epidemiology and End Results (SEER) data of the United States.
RESULTS: Over the 9 year-period, 1364 colorectal cancer cases were included. The disease incidence under age 40 years was relatively high (1.3/105) while the incidence in the age groups 40 and over was very low (12.0/105, 19.4/105 and 21.2/105 in the age groups 40-59 years, 60-69 years and > 70 years, respectively). The vast majority of tumors (97.2%) had no polyps and 37.2% of the patients presented with primary lesions in the rectum. Colorectal cancer was more common in patients from urban (55%) than rural (45%) areas. Regional differences in colon and rectal cancer incidence in the 8 districts of the study province may reflect different etiologic patterns in this population. The registry data of Egypt shows a slightly higher incidence of colorectal cancer than the United States in subjects under age 40 years. The results also shows significantly lower incidence of colorectal cancer in subjects over age 40 years compared to the same age group in the United States SEER.
CONCLUSION: Low rate of polyps, low incidence in older subjects, and high rate of rectal cancer in Egypt. Future studies should explore clinical and molecular disease patterns.
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Ozcelik H, Shi X, Chang MC, Tram E, Vlasschaert M, Di Nicola N, Kiselova A, Yee D, Goldman A, Dowar M, Sukhu B, Kandel R, Siminovitch K. Long-range PCR and next-generation sequencing of BRCA1 and BRCA2 in breast cancer. J Mol Diagn 2012; 14:467-75. [PMID: 22874498 DOI: 10.1016/j.jmoldx.2012.03.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 02/23/2012] [Accepted: 06/05/2012] [Indexed: 11/18/2022] Open
Abstract
Individuals and families carrying mutations in BRCA1 and BRCA2 (BRCA1/2) have a markedly elevated risk of developing breast and ovarian cancers. The first-generation of BRCA1/2 mutation analysis targeted only the coding exons and has implicated protein-truncating mutations (indel, nonsense) in BRCA1/2 inactivation. Recently, heritable breast cancers have also been attributed to other exonic mutations (missense, silent) and mutations in introns and untranslated regions. However, analysis of these alterations has been prohibitively laborious and cost intensive, and the proportion of cases carrying mutations in unscreened regions of BRCA1/2 and other predisposition genes is unknown. We have developed and validated a next-generation sequencing (NGS) approach for BRCA1/2 mutation analysis by applying long-range PCR and deep sequencing. Genomic DNA from familial breast cancer patients (N = 12) were screened and NGS successfully identified all 19 distinct (51 total) BRCA1 and 35 distinct (63 total) BRCA2 sequence alterations detectable by the Sanger sequencing, with no false-negative or positive results. In addition, we report the robust detection of variants from introns and untranslated regions. These results illustrate that NGS can provide comprehensive genetic information more quickly, accurately, and at a lower cost than conventional approaches, and we propose NGS to be a more effective method for BRCA1/2 mutational analysis. Advances in NGS will play an important role in enabling molecular diagnostics and personalized treatment of breast and ovarian cancers.
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Affiliation(s)
- Hilmi Ozcelik
- Fred A Litwin Centre for Cancer Genetics, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
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Spier I, Horpaopan S, Vogt S, Uhlhaas S, Morak M, Stienen D, Draaken M, Ludwig M, Holinski-Feder E, Nöthen MM, Hoffmann P, Aretz S. Deep intronic APC mutations explain a substantial proportion of patients with familial or early-onset adenomatous polyposis. Hum Mutat 2012; 33:1045-50. [PMID: 22431159 DOI: 10.1002/humu.22082] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 03/05/2012] [Indexed: 01/13/2023]
Abstract
To uncover pathogenic deep intronic variants in patients with colorectal adenomatous polyposis, in whom no germline mutation in the APC or MUTYH genes can be identified by routine diagnostics, we performed a systematic APC messenger RNA analysis in 125 unrelated mutation-negative cases. Overall, we identified aberrant transcripts in 8% of the patients (familial cases 30%; early-onset manifestation 21%). In eight of them, two different out-of-frame pseudoexons were found consisting of a 167-bp insertion from intron 4 in five families with a shared founder haplotype and a 83-bp insertion from intron 10 in three patients. The pseudoexon formation was caused by three different heterozygous germline mutations, which are supposed to activate cryptic splice sites. In conclusion, a few deep intronic mutations contribute substantially to the APC mutation spectrum. Complementary DNA analysis and/or target sequencing of intronic regions should be considered as an additional mutation discovery approach in polyposis patients.
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Affiliation(s)
- Isabel Spier
- Institute of Human Genetics, University of Bonn, Sigmund-Freud-Strasse 25,Bonn, Germany.
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Rossetti S, Hopp K, Sikkink RA, Sundsbak JL, Lee YK, Kubly V, Eckloff BW, Ward CJ, Winearls CG, Torres VE, Harris PC. Identification of gene mutations in autosomal dominant polycystic kidney disease through targeted resequencing. J Am Soc Nephrol 2012; 23:915-33. [PMID: 22383692 DOI: 10.1681/asn.2011101032] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Mutations in two large multi-exon genes, PKD1 and PKD2, cause autosomal dominant polycystic kidney disease (ADPKD). The duplication of PKD1 exons 1-32 as six pseudogenes on chromosome 16, the high level of allelic heterogeneity, and the cost of Sanger sequencing complicate mutation analysis, which can aid diagnostics of ADPKD. We developed and validated a strategy to analyze both the PKD1 and PKD2 genes using next-generation sequencing by pooling long-range PCR amplicons and multiplexing bar-coded libraries. We used this approach to characterize a cohort of 230 patients with ADPKD. This process detected definitely and likely pathogenic variants in 115 (63%) of 183 patients with typical ADPKD. In addition, we identified atypical mutations, a gene conversion, and one missed mutation resulting from allele dropout, and we characterized the pattern of deep intronic variation for both genes. In summary, this strategy involving next-generation sequencing is a model for future genetic characterization of large ADPKD populations.
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Affiliation(s)
- Sandro Rossetti
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA.
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