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Villani RM, McKenzie ME, Davidson AL, Spurdle AB. Regional-specific calibration enables application of computational evidence for clinical classification of 5' cis-regulatory variants in Mendelian disease. Am J Hum Genet 2024:S0002-9297(24)00165-4. [PMID: 38815586 DOI: 10.1016/j.ajhg.2024.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 05/02/2024] [Accepted: 05/03/2024] [Indexed: 06/01/2024] Open
Abstract
To date, clinical genetic testing for Mendelian disease variants has focused heavily on exonic coding and intronic gene regions. This multi-step study was undertaken to provide an evidence base for selecting and applying computational approaches for use in clinical classification of 5' cis-regulatory region variants. Curated datasets of clinically reported disease-causing 5' cis-regulatory region variants and variants from matched genomic regions in population controls were used to calibrate six bioinformatic tools as predictors of variant pathogenicity. Likelihood ratio estimates were aligned to code weights following ClinGen recommendations for application of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG/AMP) classification scheme. Considering code assignment across all reference dataset variants, performance was best for CADD (81.2%) and REMM (81.5%). Optimized thresholds provided moderate evidence toward pathogenicity (CADD, REMM) and moderate (CADD) or supporting (REMM) evidence against pathogenicity. Both sensitivity and specificity of prediction were improved when further categorizing variants based on location in an EPDnew-defined promoter region. Combining predictions (CADD, REMM, and location in a promoter region) increased specificity at the expense of sensitivity. Importantly, the optimal CADD thresholds for assigning ACMG/AMP codes PP3 (≥10) and BP4 (≤8) were vastly different from recommendations for protein-coding variants (PP3 ≥25.3; BP4 ≤22.7); CADD <22.7 would incorrectly assign BP4 for >90% of reported disease-causing cis-regulatory region variants. Our results demonstrate the need to consider a tiered approach and tailored score thresholds to optimize bioinformatic impact prediction for clinical classification of 5' cis-regulatory region variants.
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Affiliation(s)
- Rehan M Villani
- Population Health Program, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Maddison E McKenzie
- Population Health Program, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Aimee L Davidson
- Population Health Program, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Amanda B Spurdle
- Population Health Program, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia; University of Queensland, Brisbane, Queensland, Australia.
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Fatemi N, Tu SJ, Chung CC, Moghadam PK, Mojarad EN, Sadeghi A, Totonchi M, Aghdaei HA, Chang JG. Whole exome sequencing identifies MAP3K1, MSH2, and MLH1 as potential cancer-predisposing genes in familial early-onset colorectal cancer. Kaohsiung J Med Sci 2023; 39:896-903. [PMID: 37314251 DOI: 10.1002/kjm2.12715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 05/01/2023] [Accepted: 05/21/2023] [Indexed: 06/15/2023] Open
Abstract
The incidence of early-onset colorectal cancer (CRC), which affects people under 50, is increasing for unknown reasons. Additionally, no underlying genetic cause is found in 20%-30% of patients suspected of having familial CRC syndrome. Whole exome sequencing (WES) has generated evidence for new genes associated with CRC susceptibility, but many patients remain undiagnosed. This study applied WES in five early-onset CRC patients from three unrelated families to identify novel genetic variants that could be linked to rapid disease development. Furthermore, the candidate variants were validated using Sanger sequencing. Two heterozygote variations, c.1077-2A>G and c.199G>A, were found in the MSH2 and the MLH1 genes, respectively. Sanger sequencing analysis confirmed that these (likely) pathogenic mutations segregated in all the affected families' members. In addition, we identified a rare heterozygote variant (c.175C>T) with suspected pathogenic potential in the MAP3K1 gene; formally the variant is of uncertain significance (VUS). Our findings support the hypothesis that CRC onset may be oligogenic and molecularly heterogeneous. Larger and more robust studies are needed to understand the genetic basis of early-onset CRC development, combined with novel functional analyses and omics approaches.
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Affiliation(s)
- Nayeralsadat Fatemi
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Siang-Jyun Tu
- Center for Precision Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Chin-Chun Chung
- Center for Precision Medicine, China Medical University Hospital, Taichung, Taiwan
| | - Pardis Ketabi Moghadam
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Ehsan Nazemalhosseini Mojarad
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Amir Sadeghi
- Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mehdi Totonchi
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Genetics, Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran
| | - Hamid Asadzadeh Aghdaei
- Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Jan-Gowth Chang
- Center for Precision Medicine, China Medical University Hospital, Taichung, Taiwan
- Department of Bioinformatics and Medical Engineering, Asia University, Taichung, Taiwan
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Barbirou M, Miller AA, Mezlini A, Bouhaouala-Zahar B, Tonellato PJ. Variant Characterization of a Representative Large Pedigree Suggests "Variant Risk Clusters" Convey Varying Predisposition of Risk to Lynch Syndrome. Cancers (Basel) 2023; 15:4074. [PMID: 37627102 PMCID: PMC10452890 DOI: 10.3390/cancers15164074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/09/2023] [Accepted: 08/10/2023] [Indexed: 08/27/2023] Open
Abstract
Recently, worldwide incidences of young adult aggressive colorectal cancer (CRC) have rapidly increased. Of these incidences diagnosed as familial Lynch syndrome (LS) CRC, outcomes are extremely poor. In this study, we seek novel familial germline variants from a large pedigree Tunisian family with 12 LS-affected individuals to identify putative germline variants associated with varying risk of LS. Whole-genome sequencing analysis was performed to identify known and novel germline variants shared between affected and non-affected pedigree members. SNPs, indels, and structural variants (SVs) were computationally identified, and their oncological influence was predicted using the Genetic Association of Complex Diseases and Disorders, OncoKB, and My Cancer Genome databases. Of 94 germline familial variants identified with predicted functional impact, 37 SNPs/indels were detected in 28 genes, 2 of which (MLH1 and PRH1-TAS2R14) have known association with CRC and 4 others (PPP1R13B, LAMA5, FTO, and NLRP14) have known association with non-CRC cancers. In addition, 48 of 57 identified SVs overlap with 43 genes. Three of these genes (RELN, IRS2, and FOXP1) have a known association with non-CRC digestive cancers and one (RRAS2) has a known association with non-CRC cancer. Our study identified 83 novel, predicted functionally impactful germline variants grouped in three "variant risk clusters" shared in three familiarly associated LS groups (high, intermediate and low risk). This variant characterization study demonstrates that large pedigree investigations provide important evidence supporting the hypothesis that different "variant risk clusters" can convey different mechanisms of risk and oncogenesis of LS-CRC even within the same pedigree.
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Affiliation(s)
- Mouadh Barbirou
- Circulating Tumor Cell Core Laboratory, Population Science Division, Medical Oncology Department, Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA;
- Center for Biomedical Informatics, Department of Health Management and Informatics, School of Medicine, University of Missouri, Columbia, MI 65211, USA;
- Medical School, University of Tunis El Manar, Tunis 1068, Tunisia;
| | - Amanda A. Miller
- Circulating Tumor Cell Core Laboratory, Population Science Division, Medical Oncology Department, Medical College, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA;
- Center for Biomedical Informatics, Department of Health Management and Informatics, School of Medicine, University of Missouri, Columbia, MI 65211, USA;
| | - Amel Mezlini
- Medical Oncology Division, Salah Azeiz Oncology Institute, University of Tunis El Manar, Tunis 1068, Tunisia;
| | - Balkiss Bouhaouala-Zahar
- Medical School, University of Tunis El Manar, Tunis 1068, Tunisia;
- Laboratory of Venoms and Therapeutic Biomolecules, LR16IPT08 Institute Pasteur of Tunis, University of Tunis El Manar, Tunis 1068, Tunisia
| | - Peter J. Tonellato
- Center for Biomedical Informatics, Department of Health Management and Informatics, School of Medicine, University of Missouri, Columbia, MI 65211, USA;
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Joo JE, Mahmood K, Walker R, Georgeson P, Candiloro I, Clendenning M, Como J, Joseland S, Preston S, Graversen L, Wilding M, Field M, Lemon M, Wakeling J, Marfan H, Susman R, Isbister J, Edwards E, Bowman M, Kirk J, Ip E, McKay L, Antill Y, Hopper JL, Boussioutas A, Macrae FA, Dobrovic A, Jenkins MA, Rosty C, Winship IM, Buchanan DD. Identifying primary and secondary MLH1 epimutation carriers displaying low-level constitutional MLH1 methylation using droplet digital PCR and genome-wide DNA methylation profiling of colorectal cancers. Clin Epigenetics 2023; 15:95. [PMID: 37270516 PMCID: PMC10239107 DOI: 10.1186/s13148-023-01511-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 05/24/2023] [Indexed: 06/05/2023] Open
Abstract
BACKGROUND MLH1 epimutation is characterised by constitutional monoallelic MLH1 promoter hypermethylation, which can cause colorectal cancer (CRC). Tumour molecular profiles of MLH1 epimutation CRCs were used to classify germline MLH1 promoter variants of uncertain significance and MLH1 methylated early-onset CRCs (EOCRCs). Genome-wide DNA methylation and somatic mutational profiles of tumours from two germline MLH1: c.-11C > T and one MLH1: c.-[28A > G; 7C > T] carriers and three MLH1 methylated EOCRCs (< 45 years) were compared with 38 reference CRCs. Methylation-sensitive droplet digital PCR (ddPCR) was used to detect mosaic MLH1 methylation in blood, normal mucosa and buccal DNA. RESULTS Genome-wide methylation-based Consensus Clustering identified four clusters where the tumour methylation profiles of germline MLH1: c.-11C > T carriers and MLH1 methylated EOCRCs clustered with the constitutional MLH1 epimutation CRCs but not with the sporadic MLH1 methylated CRCs. Furthermore, monoallelic MLH1 methylation and APC promoter hypermethylation in tumour were observed in both MLH1 epimutation and germline MLH1: c.-11C > T carriers and MLH1 methylated EOCRCs. Mosaic constitutional MLH1 methylation in MLH1: c.-11C > T carriers and 1 of 3 MLH1 methylated EOCRCs was identified by methylation-sensitive ddPCR. CONCLUSIONS Mosaic MLH1 epimutation underlies the CRC aetiology in MLH1: c.-11C > T germline carriers and a subset of MLH1 methylated EOCRCs. Tumour profiling and ultra-sensitive ddPCR methylation testing can be used to identify mosaic MLH1 epimutation carriers.
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Affiliation(s)
- Jihoon E Joo
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3000, Australia.
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, Australia.
| | - Khalid Mahmood
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3000, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, Australia
- Melbourne Bioinformatics, The University of Melbourne, Melbourne, VIC, Australia
| | - Romy Walker
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3000, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, Australia
| | - Peter Georgeson
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3000, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, Australia
| | - Ida Candiloro
- Beacon Biomarkers Lab, Department of Surgery, Austin Health, University of Melbourne, Heidelberg, VIC, Australia
| | - Mark Clendenning
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3000, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, Australia
| | - Julia Como
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3000, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, Australia
| | - Sharelle Joseland
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3000, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, Australia
| | - Susan Preston
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3000, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, Australia
| | - Lise Graversen
- Department of Clinical Genetics, Aarhus University Hospital, Aarhus, Denmark
| | - Mathilda Wilding
- Department of Clinical Genetics, Royal North Shore Hospital, Sydney, NSW, Australia
| | - Michael Field
- Department of Clinical Genetics, Royal North Shore Hospital, Sydney, NSW, Australia
| | - Michelle Lemon
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
| | - Janette Wakeling
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
- Tasman Health Care, Southport, QLD, Australia
| | - Helen Marfan
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
| | - Rachel Susman
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Herston, QLD, Australia
| | - Joanne Isbister
- Genomic Medicine and Family Cancer Clinic, Royal Melbourne Hospital, Parkville, Melbourne, VIC, Australia
| | - Emma Edwards
- Familial Cancer Service, Crown Princess Mary Cancer Centre, Westmead Hospital, Sydney, NSW, 2145, Australia
| | - Michelle Bowman
- Familial Cancer Service, Crown Princess Mary Cancer Centre, Westmead Hospital, Sydney, NSW, 2145, Australia
| | - Judy Kirk
- Familial Cancer Service, Crown Princess Mary Cancer Centre, Westmead Hospital, Sydney, NSW, 2145, Australia
| | - Emilia Ip
- Department of Cancer Genetics, Liverpool Hospital, Liverpool, NSW, Australia
| | - Lynne McKay
- The Cabrini Family Cancer Clinic, Cabrini Health, Malvern, VIC, Australia
| | - Yoland Antill
- Genomic Medicine and Family Cancer Clinic, Royal Melbourne Hospital, Parkville, Melbourne, VIC, Australia
- The Cabrini Family Cancer Clinic, Cabrini Health, Malvern, VIC, Australia
| | - John L Hopper
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Carlton, VIC, Australia
| | - Alex Boussioutas
- Department of Gastroenterology, The Alfred Hospital, Melbourne, Parkville, VIC, 3010, Australia
- Central Clinical School, Monash University, Melbourne, VIC, 3004, Australia
| | - Finlay A Macrae
- Genomic Medicine and Family Cancer Clinic, Royal Melbourne Hospital, Parkville, Melbourne, VIC, Australia
- Colorectal Medicine and Genetics, The Royal Melbourne Hospital, Parkville, VIC, Australia
- Department of Medicine, The University of Melbourne, Parkville, Australia
| | - Alexander Dobrovic
- Beacon Biomarkers Lab, Department of Surgery, Austin Health, University of Melbourne, Heidelberg, VIC, Australia
| | - Mark A Jenkins
- Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, The University of Melbourne, Carlton, VIC, Australia
| | - Christophe Rosty
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3000, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, Australia
- Envoi Specialist Pathologists, Brisbane, Australia
- University of Queensland, Brisbane, Australia
| | - Ingrid M Winship
- Genomic Medicine and Family Cancer Clinic, Royal Melbourne Hospital, Parkville, Melbourne, VIC, Australia
- Department of Medicine, The University of Melbourne, Parkville, Australia
| | - Daniel D Buchanan
- Colorectal Oncogenomics Group, Department of Clinical Pathology, Victorian Comprehensive Cancer Centre, The University of Melbourne, 305 Grattan Street, Parkville, VIC, 3000, Australia
- Victorian Comprehensive Cancer Centre, University of Melbourne Centre for Cancer Research, Parkville, VIC, Australia
- Genomic Medicine and Family Cancer Clinic, Royal Melbourne Hospital, Parkville, Melbourne, VIC, Australia
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5
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Germline variants associated with breast cancer in Khakass women of North Asia. Mol Biol Rep 2023; 50:2335-2341. [PMID: 36577833 DOI: 10.1007/s11033-022-08215-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 12/15/2022] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Variants in the BRCA1/2 genes are responsible for familial breast cancer. Numerous studies showed a different spectrum of BRCA variants among breast cancer patients of different Ethnicity origin. In the available literature, no previous research has focused on breast cancer-associated variants among the Khakass people (the indigenous people of the Russian Federation). METHODS Twenty-six Khakass breast cancer patients were enrolled in the study. Genomic DNA was isolated from blood samples and used to prepare libraries using a Hereditary Cancer Solution kit. Next-generation sequencing (NGS) was performed using the MiSeq System (Illumina, USA). RESULTS In our study, 12% of patients (3/26) carried a single pathogenic variant; 54% of patients (14/26) carried variants of uncertain significance (VUS) or conflicting variants; and 35% of patients (9/26) did not carry any clinically significant variants. Germline pathogenic variant in the ATM gene (rs780619951, NC_000011.10:g.108259022C > T) was identified in two unrelated patients with a family history of cancer (7.6%, 2/26). The pathogenic truncating variant in the ATM gene (p. R805* or c.2413C > T) leads to the nonfunctional version of the protein. This variant has been earlier reported in individuals with a family history of breast cancer. CONCLUSIONS Our pilot study describes the germline variant in the ATM gene associated with breast cancer in Khakass women of North Asia.
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Seo MK, Kang H, Kim S. Tumor microenvironment-aware, single-transcriptome prediction of microsatellite instability in colorectal cancer using meta-analysis. Sci Rep 2022; 12:6283. [PMID: 35428835 PMCID: PMC9012745 DOI: 10.1038/s41598-022-10182-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 03/28/2022] [Indexed: 01/27/2023] Open
Abstract
Detecting microsatellite instability (MSI) in colorectal cancers (CRCs) is essential because it is the determinant of treatment strategies, including immunotherapy and chemotherapy. Yet, no attempt has been made to exploit transcriptomic profile and tumor microenvironment (TME) of it to unveil MSI status in CRC. Hence, we developed a novel TME-aware, single-transcriptome predictor of MSI for CRC, called MAP (Microsatellite instability Absolute single sample Predictor). MAP was developed utilizing recursive feature elimination-random forest with 466 CRC samples from The Cancer Genome Atlas, and its performance was validated in independent cohorts, including 1118 samples. MAP showed robustness and predictive power in predicting MSI status in CRC. Additional advantages for MAP were demonstrated through comparative analysis with existing MSI classifier and other cancer types. Our novel approach will provide access to untouched vast amounts of publicly available transcriptomic data and widen the door for MSI CRC research and be useful for gaining insights to help with translational medicine.
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Affiliation(s)
- Mi-Kyoung Seo
- Department of Biomedical Systems Informatics, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Hyundeok Kang
- Department of Biomedical Systems Informatics, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Sangwoo Kim
- Department of Biomedical Systems Informatics, Brain Korea 21 Project, Yonsei University College of Medicine, Seoul, 03722, South Korea.
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7
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Kingdom R, Wright CF. Incomplete Penetrance and Variable Expressivity: From Clinical Studies to Population Cohorts. Front Genet 2022; 13:920390. [PMID: 35983412 PMCID: PMC9380816 DOI: 10.3389/fgene.2022.920390] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/09/2022] [Indexed: 12/20/2022] Open
Abstract
The same genetic variant found in different individuals can cause a range of diverse phenotypes, from no discernible clinical phenotype to severe disease, even among related individuals. Such variants can be said to display incomplete penetrance, a binary phenomenon where the genotype either causes the expected clinical phenotype or it does not, or they can be said to display variable expressivity, in which the same genotype can cause a wide range of clinical symptoms across a spectrum. Both incomplete penetrance and variable expressivity are thought to be caused by a range of factors, including common variants, variants in regulatory regions, epigenetics, environmental factors, and lifestyle. Many thousands of genetic variants have been identified as the cause of monogenic disorders, mostly determined through small clinical studies, and thus, the penetrance and expressivity of these variants may be overestimated when compared to their effect on the general population. With the wealth of population cohort data currently available, the penetrance and expressivity of such genetic variants can be investigated across a much wider contingent, potentially helping to reclassify variants that were previously thought to be completely penetrant. Research into the penetrance and expressivity of such genetic variants is important for clinical classification, both for determining causative mechanisms of disease in the affected population and for providing accurate risk information through genetic counseling. A genotype-based definition of the causes of rare diseases incorporating information from population cohorts and clinical studies is critical for our understanding of incomplete penetrance and variable expressivity. This review examines our current knowledge of the penetrance and expressivity of genetic variants in rare disease and across populations, as well as looking into the potential causes of the variation seen, including genetic modifiers, mosaicism, and polygenic factors, among others. We also considered the challenges that come with investigating penetrance and expressivity.
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Affiliation(s)
- Rebecca Kingdom
- Institute of Biomedical and Clinical Science, Royal Devon & Exeter Hospital, University of Exeter Medical School, Exeter, United Kingdom
| | - Caroline F Wright
- Institute of Biomedical and Clinical Science, Royal Devon & Exeter Hospital, University of Exeter Medical School, Exeter, United Kingdom
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Jiang M, Jia K, Wang L, Li W, Chen B, Liu Y, Wang H, Zhao S, He Y, Zhou C. Alterations of DNA damage repair in cancer: from mechanisms to applications. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:1685. [PMID: 33490197 PMCID: PMC7812211 DOI: 10.21037/atm-20-2920] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
DNA damage repair (DDR) pathways are essential to ensure the accurate transmission of genetic material. However, different endogenous and exogenous factors challenge genomic integrity. Mechanisms involved in the alterations of DDR pathways mainly include genetic inactivation and epigenetic mechanisms. The development and progression of carcinomas are closely associated with DDR pathway aberrations, including the epigenetic silencing of gene O6-alkylguanine-DNA methyltransferase (MGMT); deficiencies of mismatch repair (MMR) genes, including MutL homolog 1 (MLH1), MutS protein homologue (MSH)-2 (MSH2), MSH6, and PMS1 homolog 2; the mismatch repair system component (PMS2); and mutations of homologous recombination repair (HRR) genes, such as the breast cancer susceptibility gene 1/2 (BRCA1/2). Understanding the underlying mechanisms and the correlations between alterations to DDR pathways and cancer could improve the efficacy of antitumor therapies. Emerging evidence suggests that survival is higher in patients with DDR-deficient tumors than in those with DDR-proficient tumors. Thus, DDR alterations play a predictive and prognostic role in anticancer therapies. Theoretical studies on the co-administration of DDR inhibitors and other anticancer therapies, including chemotherapy, radiotherapy, immunotherapy, endocrine therapy, and epigenetic drugs, hold promise for cancer treatments. In this review, we focus on the basic mechanisms, characteristics, current applications, and combination strategies of DDR pathways in the anticancer field.
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Affiliation(s)
- Minlin Jiang
- Department of Medical Oncology, Shanghai Pulmonary Hospital, Tongji University Medical School Cancer Institute, Tongji University School of Medicine, Shanghai, China.,Tongji University, Shanghai, China
| | - Keyi Jia
- Department of Medical Oncology, Shanghai Pulmonary Hospital, Tongji University Medical School Cancer Institute, Tongji University School of Medicine, Shanghai, China.,Tongji University, Shanghai, China
| | - Lei Wang
- Department of Medical Oncology, Shanghai Pulmonary Hospital, Tongji University Medical School Cancer Institute, Tongji University School of Medicine, Shanghai, China
| | - Wei Li
- Department of Medical Oncology, Shanghai Pulmonary Hospital, Tongji University Medical School Cancer Institute, Tongji University School of Medicine, Shanghai, China
| | - Bin Chen
- Department of Medical Oncology, Shanghai Pulmonary Hospital, Tongji University Medical School Cancer Institute, Tongji University School of Medicine, Shanghai, China
| | - Yu Liu
- Department of Medical Oncology, Shanghai Pulmonary Hospital, Tongji University Medical School Cancer Institute, Tongji University School of Medicine, Shanghai, China.,Tongji University, Shanghai, China
| | - Hao Wang
- Department of Medical Oncology, Shanghai Pulmonary Hospital, Tongji University Medical School Cancer Institute, Tongji University School of Medicine, Shanghai, China.,Tongji University, Shanghai, China
| | - Sha Zhao
- Department of Medical Oncology, Shanghai Pulmonary Hospital, Tongji University Medical School Cancer Institute, Tongji University School of Medicine, Shanghai, China
| | - Yayi He
- Department of Medical Oncology, Shanghai Pulmonary Hospital, Tongji University Medical School Cancer Institute, Tongji University School of Medicine, Shanghai, China
| | - Caicun Zhou
- Department of Medical Oncology, Shanghai Pulmonary Hospital, Tongji University Medical School Cancer Institute, Tongji University School of Medicine, Shanghai, China
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9
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Jarhelle E, Riise Stensland HMF, Hansen GÅM, Skarsfjord S, Jonsrud C, Ingebrigtsen M, Strømsvik N, Van Ghelue M. Identifying sequence variants contributing to hereditary breast and ovarian cancer in BRCA1 and BRCA2 negative breast and ovarian cancer patients. Sci Rep 2019; 9:19986. [PMID: 31882575 PMCID: PMC6934654 DOI: 10.1038/s41598-019-55515-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 11/26/2019] [Indexed: 12/21/2022] Open
Abstract
Families with breast and ovarian cancer are often tested for disease associated sequence variants in BRCA1 and BRCA2. Pathogenic sequence variants (PVs) in these two genes are known to increase breast and ovarian cancer risks in females. However, in most families no PVs are detected in these two genes. Currently, several studies have identified other genes involved in hereditary breast and ovarian cancer (HBOC). To identify genetic risk factors for breast and ovarian cancer in a Norwegian HBOC cohort, 101 breast and/or ovarian cancer patients negative for PVs and variants of unknown clinical significance (VUS) in BRCA1/2 were screened for PVs in 94 genes using next-generation sequencing. Sixteen genes were closely scrutinized. Nine different deleterious germline PVs/likely pathogenic variants (LPVs) were identified in seven genes in 12 patients: three in ATM, and one in CHEK2, ERCC5, FANCM, RAD51C, TP53 and WRN. Additionally, 32 different VUSs were identified and these require further characterization. For carriers of PV/LPV in many of these genes, there are no national clinical management programs in Norway. The diversity of genetic risk factors possibly involved in cancer development show the necessity for more knowledge to improve the clinical follow-up of this genetically diverse patient group.
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Affiliation(s)
- Elisabeth Jarhelle
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway. .,Department of Clinical Medicine, University of Tromsø, Tromsø, Norway. .,Northern Norway Family Cancer Center, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway.
| | - Hilde Monica Frostad Riise Stensland
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway.,Northern Norway Family Cancer Center, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway
| | - Geir Åsmund Myge Hansen
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway.,Northern Norway Family Cancer Center, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway
| | - Siri Skarsfjord
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway
| | - Christoffer Jonsrud
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway.,Northern Norway Family Cancer Center, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway
| | - Monica Ingebrigtsen
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway
| | - Nina Strømsvik
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway.,Northern Norway Family Cancer Center, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway.,Department of Health and Caring Sciences, Western Norway University of Applied Sciences, Bergen, Norway
| | - Marijke Van Ghelue
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, Tromsø, Norway. .,Department of Clinical Medicine, University of Tromsø, Tromsø, Norway. .,Northern Norway Family Cancer Center, Department of Medical Genetics, University Hospital of North Norway, Tromsø, Norway.
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10
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Larouche V, Akirov A, Thain E, Kim RH, Ezzat S. Co-occurrence of breast cancer and neuroendocrine tumours: New genetic insights beyond Multiple Endocrine Neoplasia syndromes. Endocrinol Diabetes Metab 2019; 2:e00092. [PMID: 31592449 PMCID: PMC6775469 DOI: 10.1002/edm2.92] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Accepted: 08/16/2019] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE Age-standardized incidence of female breast cancer is 145.1 per 100000/year and 5.86 per 100000/year for neuroendocrine tumours (NET) in Canada. Evidence is scarce about gene variants that may predispose patients to develop both neoplasms. The objective of this study was to identify germline gene variants associated with this combination of tumours. DESIGN AND PATIENTS A retrospective chart review (2007-2018) in a tertiary NET referral centre was completed. A series of 9 female patients with concurrent breast cancer and NET is presented. All patients underwent a 37 gene hereditary cancer next-generation sequencing panel. RESULTS Mean age was 61.4 years (35-85) at breast cancer diagnosis and 63.4 years (51-89) at NET diagnosis. Four patients had a pancreatic, three had a small bowel and two had a lung NET. Two patients were known cases of MEN1, and one patient was found to harbour a pathogenic variant in MEN1 and a variant of unknown significance (VUS) in ATM. A second patient was found to harbour a pathogenic variant in APC. A third patient was found to carry a pathogenic variant in PALB2 as well as a VUS in FANCM, MLH1 and STK11. Another patient was found to harbour a VUS in MSH2. One patient was found to carry a pathogenic variant in NTHL1. CONCLUSION The first cases of a PALB2, an APC and a NTHL1 pathogenic variants in patients with both breast cancer and NET were presented. NGS testing should be considered in specific patients with this combination of neoplasms, as certain germline variants beyond MEN1, have important implications for cancer surveillance.
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Affiliation(s)
- Vincent Larouche
- Division of Endocrinology and MetabolismDepartment of MedicineUniversity Health NetworkUniversity of TorontoTorontoOntarioCanada
- Division of Endocrinology and MetabolismJewish General HospitalMcGill UniversityMontrealQuebecCanada
| | - Amit Akirov
- Division of Endocrinology and MetabolismDepartment of MedicineUniversity Health NetworkUniversity of TorontoTorontoOntarioCanada
| | - Emily Thain
- Familial Cancer ClinicPrincess Margaret Cancer CentreUniversity Health NetworkTorontoOntarioCanada
| | - Raymond H. Kim
- Fred A Litwin Family Centre in Genetic MedicineUniversity Health NetworkTorontoOntarioCanada
- Division of Medical OncologyDepartment of MedicineUniversity of TorontoTorontoOntarioCanada
| | - Shereen Ezzat
- Division of Endocrinology and MetabolismDepartment of MedicineUniversity Health NetworkUniversity of TorontoTorontoOntarioCanada
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11
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Morak M, Schaefer K, Steinke-Lange V, Koehler U, Keinath S, Massdorf T, Mauracher B, Rahner N, Bailey J, Kling C, Haeusser T, Laner A, Holinski-Feder E. Full-length transcript amplification and sequencing as universal method to test mRNA integrity and biallelic expression in mismatch repair genes. Eur J Hum Genet 2019; 27:1808-1820. [PMID: 31332305 DOI: 10.1038/s41431-019-0472-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/13/2019] [Accepted: 07/02/2019] [Indexed: 12/13/2022] Open
Abstract
In pathogenicity assessment, RNA-based analyses are important for the correct classification of variants, and require gene-specific cut-offs for allelic representation and alternative/aberrant splicing. Beside this, the diagnostic yield of RNA-based techniques capable to detect aberrant splicing or allelic loss due to intronic/regulatory variants has to be elaborated. We established a cDNA analysis for full-length transcripts (FLT) of the four DNA mismatch repair (MMR) genes to investigate the splicing pattern and transcript integrity with active/inhibited nonsense-mediated mRNA-decay (NMD). Validation was based on results from normal controls, samples with premature termination codons (PTC), samples with splice-site defects (SSD), and samples with pathogenic putative missense variants. The method was applied to patients with variants of uncertain significance (VUS) or unexplained immunohistochemical MMR deficiency. We categorized the allelic representation into biallelic (50 ± 10%) or allelic loss (≤10%), and >10% and <40% as unclear. We defined isoforms up to 10% and exon-specific exceptions as alternative splicing, set the cut-off for SSD in cDNA + P to 30-50%, and regard >10% and <30% as unclear. FLT cDNA analyses designated 16% of all putative missense variants and 12% of VUS as SSD, detected MMR-defects in 19% of the unsolved patients, and re-classified >30% of VUS. Our method allows a standardized, systematic cDNA analysis of the MMR FLTs to assess the pathogenicity mechanism of VUS on RNA level, which will gain relevance for precision medicine and gene therapy. Diagnostic accuracy will be enhanced by detecting MMR defects in hitherto unsolved patients. The data generated will help to calibrate a high-throughput NGS-based mRNA-analysis and optimize prediction programs.
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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 - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany.
| | - Kerstin Schaefer
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, 80336, Munich, Germany
| | - Verena Steinke-Lange
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, 80336, Munich, Germany.,MGZ - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany
| | - Udo Koehler
- MGZ - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany
| | - Susanne Keinath
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, 80336, Munich, Germany
| | - Trisari Massdorf
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, 80336, Munich, Germany.,MGZ - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany
| | - Brigitte Mauracher
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, 80336, Munich, Germany
| | - Nils Rahner
- Medical Faculty, Institute of Human Genetics, Heinrich-Heine University, Düsseldorf, Germany
| | - Jessica Bailey
- Clinical Genetics, St. George's University Hospital NHS Foundation Trust, London, UK
| | | | - Tanja Haeusser
- MGZ - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany
| | - Andreas Laner
- MGZ - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany
| | - Elke Holinski-Feder
- Medizinische Klinik und Poliklinik IV, Campus Innenstadt, Klinikum der Universität München, Ziemssenstr. 1, 80336, Munich, Germany. .,MGZ - Medical Genetics Center, Bayerstr. 3-5, 80335, Munich, Germany.
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12
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The Clinical Utility of Epigenetics: A Case Study. Clin Epigenetics 2019. [DOI: 10.1007/978-981-13-8958-0_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
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13
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A Novel MLH1 Initiation Codon Mutation (c.3G>T) in a Large Chinese Lynch Syndrome Family with Different Onset Age and mRNA Expression Level. BIOMED RESEARCH INTERNATIONAL 2018; 2018:1460835. [PMID: 30539002 PMCID: PMC6261076 DOI: 10.1155/2018/1460835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 10/26/2018] [Accepted: 11/04/2018] [Indexed: 01/17/2023]
Abstract
Lynch syndrome is a genetically and clinically heterogeneous disorder; it is caused by a germline mutation in DNA mismatch repair (MMR) genes. Individuals with a heterozygous mutation in MLH1 have an increased risk for developing colorectal cancer. Here we described a 5-generation Chinese Lynch syndrome family with different severity and onset age. A novel heterozygous germline mutation (c.3G>T, p.Met1Ile) in MLH1 gene was discovered by next generation sequencing. Our study also revealed by qPCR that the MLH1 mRNA expression in peripheral blood of patients in this family was remarkably lower than that of the unaffected carriers and non-carriers. The research results indicated that the mRNA expression level may provide predictive suggestions of treatment and management for carriers with the initiation codon mutation of MLH1 in this family. Further studies are undertaken in this family as well as other families with Lynch syndrome to interrogate the exact reasons affecting the MLH1 mRNA expression level and whether mRNA expression in peripheral blood could be a significant factor for early diagnosis and surveillance of Lynch syndrome.
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14
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Müller D, Telieps T, Eugster A, Weinzierl C, Jolink M, Ziegler AG, Bonifacio E. Novel minor HLA DR associated antigens in type 1 diabetes. Clin Immunol 2018; 194:87-91. [PMID: 29990590 DOI: 10.1016/j.clim.2018.07.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 06/04/2018] [Accepted: 07/01/2018] [Indexed: 12/12/2022]
Abstract
Type 1 diabetes is an autoimmune disease leading to insulin deficiency. Autoantibodies to beta cell proteins are already present in the asymptomatic phase of type 1 diabetes. Recent findings have suggested a number of additional minor autoantigens in patients with type 1 diabetes. We have established luciferase immunoprecipitation systems (LIPS) for anti-MTIF3, anti-PPIL2, anti-NUP50 and anti-MLH1 and analyzed samples from 500 patients with type 1 diabetes at onset of clinical disease and 200 healthy individuals who had a family history of type 1 diabetes but no evidence of beta cell autoantibodies. We show significantly higher frequencies of anti-MTIF3, anti-PPIL2 and anti-MLH1 in recent onset type 1 diabetes patients in comparison to controls. In addition, antibodies to NUP50 were associated with HLA-DRB1*03 and antibodies to MLH1 were associated with HLA-DRB1*04 genotypes.
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Affiliation(s)
- Denise Müller
- DFG Research Center for Regenerative Therapies Dresden, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Tanja Telieps
- Helmholtz Zentrum München, Institute for Diabetes and Obesity, Neuherberg, Germany
| | - Anne Eugster
- DFG Research Center for Regenerative Therapies Dresden, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
| | - Christina Weinzierl
- Institute of Diabetes Research, Helmholtz Zentrum München, and Forschergruppe Diabetes, Klinikum rechts der Isar, Technische Universität München, Neuherberg, Germany
| | - Manja Jolink
- Institute of Diabetes Research, Helmholtz Zentrum München, and Forschergruppe Diabetes, Klinikum rechts der Isar, Technische Universität München, Neuherberg, Germany
| | - Anette-Gabriele Ziegler
- Institute of Diabetes Research, Helmholtz Zentrum München, and Forschergruppe Diabetes, Klinikum rechts der Isar, Technische Universität München, Neuherberg, Germany; Forschergruppe Diabetes e.V, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Ezio Bonifacio
- DFG Research Center for Regenerative Therapies Dresden, Faculty of Medicine, Technische Universität Dresden, Dresden, Germany; Helmholtz Zentrum München, Institute for Diabetes and Obesity, Neuherberg, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Paul Langerhans Institute Dresden, German Center for Diabetes Research (DZD), Technische Universität Dresden, Dresden, Germany.
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15
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Liu Q, Thoms JAI, Nunez AC, Huang Y, Knezevic K, Packham D, Poulos RC, Williams R, Beck D, Hawkins NJ, Ward RL, Wong JWH, Hesson LB, Sloane MA, Pimanda JE. Disruption of a -35 kb Enhancer Impairs CTCF Binding and MLH1 Expression in Colorectal Cells. Clin Cancer Res 2018; 24:4602-4611. [PMID: 29898989 DOI: 10.1158/1078-0432.ccr-17-3678] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 04/17/2018] [Accepted: 06/06/2018] [Indexed: 11/16/2022]
Abstract
Purpose:MLH1 is a major tumor suppressor gene involved in the pathogenesis of Lynch syndrome and various sporadic cancers. Despite their potential pathogenic importance, genomic regions capable of regulating MLH1 expression over long distances have yet to be identified.Experimental Design: Here, we use chromosome conformation capture (3C) to screen a 650-kb region flanking the MLH1 locus to identify interactions between the MLH1 promoter and distal regions in MLH1-expressing and nonexpressing cells. Putative enhancers were functionally validated using luciferase reporter assays, chromatin immunoprecipitation, and CRISPR-Cas9-mediated deletion of endogenous regions. To evaluate whether germline variants in the enhancer might contribute to impaired MLH1 expression in patients with suspected Lynch syndrome, we also screened germline DNA from a cohort of 74 patients with no known coding mutations or epimutations at the MLH1 promoter.Results: A 1.8-kb DNA fragment, 35 kb upstream of the MLH1 transcription start site enhances MLH1 gene expression in colorectal cells. The enhancer was bound by CTCF and CRISPR-Cas9-mediated deletion of a core binding region impairs endogenous MLH1 expression. A total of 5.4% of suspected Lynch syndrome patients have a rare single-nucleotide variant (G > A; rs143969848; 2.5% in gnomAD European, non-Finnish) within a highly conserved CTCF-binding motif, which disrupts enhancer activity in SW620 colorectal carcinoma cells.Conclusions: A CTCF-bound region within the MLH1-35 enhancer regulates MLH1 expression in colorectal cells and is worthy of scrutiny in future genetic screening strategies for suspected Lynch syndrome associated with loss of MLH1 expression. Clin Cancer Res; 24(18); 4602-11. ©2018 AACR.
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Affiliation(s)
- Qing Liu
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
| | - Julie A I Thoms
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
- School of Medical Sciences, UNSW Sydney, Sydney, New South Wales, Australia
| | - Andrea C Nunez
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
| | - Yizhou Huang
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
- Centre for Health Technologies and the School of Software, University of Technology, Sydney, New South Wales, Australia
| | - Kathy Knezevic
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
| | - Deborah Packham
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
| | - Rebecca C Poulos
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
| | - Rachel Williams
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
- Hereditary Cancer Clinic, Prince of Wales Hospital, Randwick, New South Wales, Australia
| | - Dominik Beck
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
- Centre for Health Technologies and the School of Software, University of Technology, Sydney, New South Wales, Australia
| | - Nicholas J Hawkins
- School of Medical Sciences, UNSW Sydney, Sydney, New South Wales, Australia
- School of Medicine, The University of Queensland, Brisbane, Queensland, Australia
| | - Robyn L Ward
- School of Medicine, The University of Queensland, Brisbane, Queensland, Australia
- Level 3, Brian Wilson Chancellery, The University of Queensland, Brisbane, Queensland, Australia
| | - Jason W H Wong
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
| | - Luke B Hesson
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia.
- Genome.One, Kinghorn Centre for Clinical Genomics, Garvan Institute of Medical Research, Darlinghurst, New South Wales, Australia
| | - Mathew A Sloane
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia.
- Australian Museum, Sydney, New South Wales, Australia
| | - John E Pimanda
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Sydney, Sydney, New South Wales, Australia.
- School of Medical Sciences, UNSW Sydney, Sydney, New South Wales, Australia
- Department of Haematology, Prince of Wales Hospital, Randwick, New South Wales, Australia
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16
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Morak M, Ibisler A, Keller G, Jessen E, Laner A, Gonzales-Fassrainer D, Locher M, Massdorf T, Nissen AM, Benet-Pagès A, Holinski-Feder E. Comprehensive analysis of the MLH1 promoter region in 480 patients with colorectal cancer and 1150 controls reveals new variants including one with a heritable constitutional MLH1 epimutation. J Med Genet 2018; 55:240-248. [PMID: 29472279 DOI: 10.1136/jmedgenet-2017-104744] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 10/27/2017] [Accepted: 10/30/2017] [Indexed: 01/28/2023]
Abstract
BACKGROUND Germline defects in MLH1, MSH2, MSH6 and PMS2 predisposing for Lynch syndrome (LS) are mainly based on sequence changes, whereas a constitutional epimutation of MLH1(CEM) is exceptionally rare. This abnormal MLH1 promoter methylation is not hereditary when arising de novo, whereas a stably heritable and variant-induced CEM was described for one single allele. We searched for MLH1 promoter variants causing a germline or somatic methylation induction or transcriptional repression. METHODS We analysed the MLH1 promoter sequence in five different patient groups with colorectal cancer (CRC) (n=480) composed of patients with i) CEM (n=16), ii) unsolved loss of MLH1 expression in CRC (n=37), iii) CpG-island methylator-phenotype CRC (n=102), iv) patients with LS (n=83) and v) MLH1-proficient CRC (n=242) as controls. 1150 patients with non-LS tumours also served as controls to correctly judge the results. RESULTS We detected 10 rare MLH1 promoter variants. One novel, complex MLH1 variant c.-63_-58delins18 is present in a patient with CRC with CEM and his sister, both showing a complete allele-specific promoter methylation and transcriptional silencing. The other nine promoter variants detected in 17 individuals were not associated with methylation. For four of these, a normal, biallelic MLH1 expression was found in the patients' cDNA. CONCLUSION We report the second promoter variant stably inducing a hereditary CEM. Concerning the classification of promoter variants, we discuss contradictory results from the literature for two variants, describe classification discrepancies between existing rules for five variants, suggest the (re-)classification of five promoter variants to (likely) benign and regard four variants as functionally unclear.
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Affiliation(s)
- Monika Morak
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Munich, Bavaria, Germany.,Center of Medical Genetics, Medizinisch Genetisches Zentrum, Munich, Bavaria, Germany
| | - Ayseguel Ibisler
- Department of Human Genetics, Ruhr University Bochum, Bochum, North Rhine-Westphalia, Germany
| | - Gisela Keller
- Institute of Pathology, Technical University Munich, Munich, Bavaria, Germany
| | - Ellen Jessen
- Praxis für Humangenetik, Praxis für Humangenetik, Hamburg, Hamburg, Germany
| | - Andreas Laner
- Center of Medical Genetics, Medizinisch Genetisches Zentrum, Munich, Bavaria, Germany
| | | | - Melanie Locher
- Center of Medical Genetics, Medizinisch Genetisches Zentrum, Munich, Bavaria, Germany
| | - Trisari Massdorf
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Munich, Bavaria, Germany
| | - Anke M Nissen
- Center of Medical Genetics, Medizinisch Genetisches Zentrum, Munich, Bavaria, Germany
| | - Anna Benet-Pagès
- Center of Medical Genetics, Medizinisch Genetisches Zentrum, Munich, Bavaria, Germany
| | - Elke Holinski-Feder
- Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Munich, Bavaria, Germany.,Center of Medical Genetics, Medizinisch Genetisches Zentrum, Munich, Bavaria, Germany
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17
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Pinto D, Pinto C, Guerra J, Pinheiro M, Santos R, Vedeld HM, Yohannes Z, Peixoto A, Santos C, Pinto P, Lopes P, Lothe R, Lind GE, Henrique R, Teixeira MR. Contribution of MLH1 constitutional methylation for Lynch syndrome diagnosis in patients with tumor MLH1 downregulation. Cancer Med 2018; 7:433-444. [PMID: 29341452 PMCID: PMC6193414 DOI: 10.1002/cam4.1285] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/14/2017] [Accepted: 11/16/2017] [Indexed: 12/23/2022] Open
Abstract
Constitutional epimutation of the two major mismatch repair genes, MLH1 and MSH2, has been identified as an alternative mechanism that predisposes to the development of Lynch syndrome. In the present work, we aimed to investigate the prevalence of MLH1 constitutional methylation in colorectal cancer (CRC) patients with abnormal expression of the MLH1 protein in their tumors. In a series of 38 patients who met clinical criteria for Lynch syndrome genetic testing, with loss of MLH1 expression in the tumor and with no germline mutations in the MLH1 gene (35/38) or with tumors presenting the BRAF p.Val600Glu mutation (3/38), we screened for constitutional methylation of the MLH1 gene promoter using methylation‐specific multiplex ligation‐dependent probe amplification (MS‐MLPA) in various biological samples. We found four (4/38; 10.5%) patients with constitutional methylation in the MLH1 gene promoter. RNA studies demonstrated decreased MLH1 expression in the cases with constitutional methylation when compared with controls. We could infer the mosaic nature of MLH1 constitutional hypermethylation in tissues originated from different embryonic germ layers, and in one family we could show that it occurred de novo. We conclude that constitutional MLH1 methylation occurs in a significant proportion of patients who have loss of MLH1 protein expression in their tumors and no MLH1 pathogenic germline mutation. Furthermore, we provide evidence that MLH1 constitutional hypermethylation is the molecular mechanism behind about 3% of Lynch syndrome families diagnosed in our institution, especially in patients with early onset or multiple primary tumors without significant family history.
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Affiliation(s)
- Diana Pinto
- Cancer Genetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Carla Pinto
- Cancer Genetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Joana Guerra
- Cancer Genetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Manuela Pinheiro
- Cancer Genetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Rui Santos
- Cancer Genetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Hege Marie Vedeld
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Norway
| | - Zeremariam Yohannes
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Norway
| | - Ana Peixoto
- Cancer Genetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Catarina Santos
- Cancer Genetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Pedro Pinto
- Cancer Genetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Paula Lopes
- Department of Pathology, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Cancer Biology and Epigenetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal
| | - Ragnhild Lothe
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Norway
| | - Guro Elisabeth Lind
- Department of Molecular Oncology, Institute for Cancer Research, Oslo University Hospital, Norway
| | - Rui Henrique
- Department of Pathology, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Cancer Biology and Epigenetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
| | - Manuel R Teixeira
- Cancer Genetics Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Department of Genetics, Portuguese Oncology Institute of Porto (IPO Porto), Porto, Portugal.,Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
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18
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Dos Santos ES, Caputo SM, Castera L, Gendrot M, Briaux A, Breault M, Krieger S, Rogan PK, Mucaki EJ, Burke LJ, Bièche I, Houdayer C, Vaur D, Stoppa-Lyonnet D, Brown MA, Lallemand F, Rouleau E. Assessment of the functional impact of germline BRCA1/2 variants located in non-coding regions in families with breast and/or ovarian cancer predisposition. Breast Cancer Res Treat 2017; 168:311-325. [PMID: 29236234 DOI: 10.1007/s10549-017-4602-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 11/28/2017] [Indexed: 12/19/2022]
Abstract
PURPOSE The molecular mechanism of breast and/or ovarian cancer susceptibility remains unclear in the majority of patients. While germline mutations in the regulatory non-coding regions of BRCA1 and BRCA2 genes have been described, screening has generally been limited to coding regions. The aim of this study was to evaluate the contribution of BRCA1/2 non-coding variants. METHODS Four BRCA1/2 non-coding regions were screened using high-resolution melting analysis/Sanger sequencing or next-generation sequencing on DNA extracted from index cases with breast and ovarian cancer predisposition (3926 for BRCA1 and 3910 for BRCA2). The impact of a set of variants on BRCA1/2 gene regulation was evaluated by site-directed mutagenesis, transfection, followed by Luciferase gene reporter assay. RESULTS We identified a total of 117 variants and tested twelve BRCA1 and 8 BRCA2 variants mapping to promoter and intronic regions. We highlighted two neighboring BRCA1 promoter variants (c.-130del; c.-125C > T) and one BRCA2 promoter variants (c.-296C > T) inhibiting significantly the promoter activity. In the functional assays, a regulating region within the intron 12 was found with the same enhancing impact as within the intron 2. Furthermore, the variants c.81-3980A > G and c.4186-2022C > T suppress the positive effect of the introns 2 and 12, respectively, on the BRCA1 promoter activity. We also found some variants inducing the promoter activities. CONCLUSION In this study, we highlighted some variants among many, modulating negatively the promoter activity of BRCA1 or 2 and thus having a potential impact on the risk of developing cancer. This selection makes it possible to conduct future validation studies on a limited number of variants.
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Affiliation(s)
- E Santana Dos Santos
- Department of Oncology, Center for Translational Oncology, Cancer Institute of the State of São Paulo - ICESP, São Paulo, Brazil
- Service de Génétique, Institut Curie, Paris, France
- A.C.Camargo Cancer Center, São Paulo, Brazil
| | - S M Caputo
- Service de Génétique, Institut Curie, Paris, France
| | - L Castera
- Laboratoire de Biologie et de Génétique du Cancer, CLCC François Baclesse, INSERM 1079 Centre Normand de Génomique et de MédecinePersonnalisée, Caen, France
| | - M Gendrot
- Service de Génétique, Institut Curie, Paris, France
| | - A Briaux
- Service de Génétique, Institut Curie, Paris, France
| | - M Breault
- Service de Génétique, Institut Curie, Paris, France
| | - S Krieger
- Laboratoire de Biologie et de Génétique du Cancer, CLCC François Baclesse, INSERM 1079 Centre Normand de Génomique et de MédecinePersonnalisée, Caen, France
| | - P K Rogan
- Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - E J Mucaki
- Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
| | - L J Burke
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - I Bièche
- Service de Génétique, Institut Curie, Paris, France
- Université Paris Descartes, Paris, France
| | - C Houdayer
- Service de Génétique, Institut Curie, Paris, France
- Université Paris Descartes, Paris, France
| | - D Vaur
- Laboratoire de Biologie et de Génétique du Cancer, CLCC François Baclesse, INSERM 1079 Centre Normand de Génomique et de MédecinePersonnalisée, Caen, France
| | - D Stoppa-Lyonnet
- Service de Génétique, Institut Curie, Paris, France
- Université Paris Descartes, Paris, France
| | - M A Brown
- School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Australia
| | - F Lallemand
- Service de Génétique, Institut Curie, Paris, France.
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19
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Hahn MM, de Voer RM, Hoogerbrugge N, Ligtenberg MJL, Kuiper RP, van Kessel AG. The genetic heterogeneity of colorectal cancer predisposition - guidelines for gene discovery. Cell Oncol (Dordr) 2016; 39:491-510. [PMID: 27279102 PMCID: PMC5121185 DOI: 10.1007/s13402-016-0284-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/27/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Colorectal cancer (CRC) is a cumulative term applied to a clinically and genetically heterogeneous group of neoplasms that occur in the bowel. Based on twin studies, up to 45 % of the CRC cases may involve a heritable component. Yet, only in 5-10 % of these cases high-penetrant germline mutations are found (e.g. mutations in APC and DNA mismatch repair genes) that result in a familial aggregation and/or an early onset of the disease. Genome-wide association studies have revealed that another ~5 % of the CRC cases may be explained by a cumulative effect of low-penetrant risk factors. Recent attempts to identify novel genetic factors using whole exome and whole genome sequencing has proven to be difficult since the remaining, yet to be discovered, high penetrant CRC predisposing genes appear to be rare. In addition, most of the moderately penetrant candidate genes identified so far have not been confirmed in independent cohorts. Based on literature examples, we here discuss how careful patient and cohort selection, candidate gene and variant selection, and corroborative evidence may be employed to facilitate the discovery of novel CRC predisposing genes. CONCLUSIONS The picture emerges that the genetic predisposition to CRC is heterogeneous, involving complex interplays between common and rare (inter)genic variants with different penetrances. It is anticipated, however, that the use of large clinically well-defined patient and control datasets, together with improved functional and technical possibilities, will yield enough power to unravel this complex interplay and to generate accurate individualized estimates for the risk to develop CRC.
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Affiliation(s)
- M M Hahn
- Department of Human Genetics, Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - R M de Voer
- Department of Human Genetics, Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - N Hoogerbrugge
- Department of Human Genetics, Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - M J L Ligtenberg
- Department of Human Genetics, Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - R P Kuiper
- Department of Human Genetics, Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - A Geurts van Kessel
- Department of Human Genetics, Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
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20
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Family-Specific Variants and the Limits of Human Genetics. Trends Mol Med 2016; 22:925-934. [PMID: 27742414 DOI: 10.1016/j.molmed.2016.09.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 09/10/2016] [Accepted: 09/13/2016] [Indexed: 01/28/2023]
Abstract
Every single-nucleotide change compatible with life is present in the human population today. Understanding these rare human variants defines an extraordinary challenge for genetics and medicine. The new clinical practice of sequencing many genes for hereditary cancer risk has illustrated the utility of clinical next-generation sequencing in adults, identifying more medically actionable variants than single-gene testing. However, it has also revealed a linear relationship between the length of DNA evaluated and the number of rare 'variants of uncertain significance' reported. We propose that careful approaches to phenotype-genotype inference, distinguishing between diagnostic and screening intent, in conjunction with expanded use of family-scale genetics studies as a source of information on family-specific variants, will reduce variants of uncertain significance reported to patients.
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21
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Hesson LB, Ng B, Zarzour P, Srivastava S, Kwok CT, Packham D, Nunez AC, Beck D, Ryan R, Dower A, Ford CE, Pimanda JE, Sloane MA, Hawkins NJ, Bourke MJ, Wong JWH, Ward RL. Integrated Genetic, Epigenetic, and Transcriptional Profiling Identifies Molecular Pathways in the Development of Laterally Spreading Tumors. Mol Cancer Res 2016; 14:1217-1228. [PMID: 27671336 DOI: 10.1158/1541-7786.mcr-16-0175] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 08/15/2016] [Accepted: 09/07/2016] [Indexed: 11/16/2022]
Abstract
Laterally spreading tumors (LST) are colorectal adenomas that develop into extremely large lesions with predominantly slow progression to cancer, depending on lesion subtype. Comparing and contrasting the molecular profiles of LSTs and colorectal cancers offers an opportunity to delineate key molecular alterations that drive malignant transformation in the colorectum. In a discovery cohort of 11 LSTs and paired normal mucosa, we performed a comprehensive and unbiased screen of the genome, epigenome, and transcriptome followed by bioinformatics integration of these data and validation in an additional 84 large, benign colorectal lesions. Mutation rates in LSTs were comparable with microsatellite-stable colorectal cancers (2.4 vs. 2.6 mutations per megabase); however, copy number alterations were infrequent (averaging only 1.5 per LST). Frequent genetic, epigenetic, and transcriptional alterations were identified in genes not previously implicated in colorectal neoplasia (ANO5, MED12L, EPB41L4A, RGMB, SLITRK1, SLITRK5, NRXN1, ANK2). Alterations to pathways commonly mutated in colorectal cancers, namely, the p53, PI3K, and TGFβ pathways, were rare. Instead, LST-altered genes converged on axonal guidance, Wnt, and actin cytoskeleton signaling. These integrated omics data identify molecular features associated with noncancerous LSTs and highlight that mutation load, which is relatively high in LSTs, is a poor predictor of invasive potential. IMPLICATIONS The novel genetic, epigenetic, and transcriptional changes associated with LST development reveal important insights into why some adenomas do not progress to cancer. The finding that LSTs exhibit a mutational load similar to colorectal carcinomas has implications for the validity of molecular biomarkers for assessing cancer risk. Mol Cancer Res; 14(12); 1217-28. ©2016 AACR.
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Affiliation(s)
- Luke B Hesson
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia.
| | - Benedict Ng
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia
| | - Peter Zarzour
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia
| | - Sameer Srivastava
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia.,Department of Biotechnology, Motilal Nehru National Institute of Technology, Allahabad, India
| | - Chau-To Kwok
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia
| | - Deborah Packham
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia
| | - Andrea C Nunez
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia
| | - Dominik Beck
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia
| | - Regina Ryan
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia
| | - Ashraf Dower
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia
| | - Caroline E Ford
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia
| | - John E Pimanda
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia
| | - Mathew A Sloane
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia
| | - Nicholas J Hawkins
- School of Medical Sciences, UNSW Australia, Kensington, Sydney, Australia
| | - Michael J Bourke
- Department of Gastroenterology, Westmead Hospital, Sydney, New South Wales, Australia
| | - Jason W H Wong
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia
| | - Robyn L Ward
- Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, UNSW Australia, Sydney, New South Wales, Australia. .,Level 3 Brian Wilson Chancellery, The University of Queensland, Brisbane, Queensland, Australia
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22
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Poulos RC, Sloane MA, Hesson LB, Wong JWH. The search for cis-regulatory driver mutations in cancer genomes. Oncotarget 2016; 6:32509-25. [PMID: 26356674 PMCID: PMC4741709 DOI: 10.18632/oncotarget.5085] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 08/06/2015] [Indexed: 12/16/2022] Open
Abstract
With the advent of high-throughput and relatively inexpensive whole-genome sequencing technology, the focus of cancer research has begun to shift toward analyses of somatic mutations in non-coding cis-regulatory elements of the cancer genome. Cis-regulatory elements play an important role in gene regulation, with mutations in these elements potentially resulting in changes to the expression of linked genes. The recent discoveries of recurrent TERT promoter mutations in melanoma, and recurrent mutations that create a super-enhancer regulating TAL1 expression in T-cell acute lymphoblastic leukaemia (T-ALL), have sparked significant interest in the search for other somatic cis-regulatory mutations driving cancer development. In this review, we look more closely at the TERT promoter and TAL1 enhancer alterations and use these examples to ask whether other cis-regulatory mutations may play a role in cancer susceptibility. In doing so, we make observations from the data emerging from recent research in this field, and describe the experimental and analytical approaches which could be adopted in the hope of better uncovering the true functional significance of somatic cis-regulatory mutations in cancer.
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Affiliation(s)
- Rebecca C Poulos
- Prince of Wales Clinical School and Lowy Cancer Research Centre, UNSW Australia, Sydney, Australia
| | - Mathew A Sloane
- Prince of Wales Clinical School and Lowy Cancer Research Centre, UNSW Australia, Sydney, Australia
| | - Luke B Hesson
- Prince of Wales Clinical School and Lowy Cancer Research Centre, UNSW Australia, Sydney, Australia
| | - Jason W H Wong
- Prince of Wales Clinical School and Lowy Cancer Research Centre, UNSW Australia, Sydney, Australia
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23
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Liu Q, Thompson BA, Ward RL, Hesson LB, Sloane MA. Understanding the Pathogenicity of Noncoding Mismatch Repair Gene Promoter Variants in Lynch Syndrome. Hum Mutat 2016; 37:417-26. [DOI: 10.1002/humu.22971] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 02/05/2016] [Indexed: 01/04/2023]
Affiliation(s)
- Qing Liu
- Adult Cancer Program; Lowy Cancer Research Centre and Prince of Wales Clinical School; UNSW Australia; Sydney New South Wales Australia
| | - Bryony A. Thompson
- Huntsman Cancer Institute; University of Utah; Salt Lake City Utah
- Centre for Epidemiology and Biostatistics; Melbourne School of Population and Global Health; University of Melbourne; Melbourne Victoria Australia
| | - Robyn L. Ward
- Adult Cancer Program; Lowy Cancer Research Centre and Prince of Wales Clinical School; UNSW Australia; Sydney New South Wales Australia
- Level 3 Brian Wilson Chancellery; The University of Queensland; Brisbane Queensland Australia
| | - Luke B. Hesson
- Adult Cancer Program; Lowy Cancer Research Centre and Prince of Wales Clinical School; UNSW Australia; Sydney New South Wales Australia
| | - Mathew A. Sloane
- Adult Cancer Program; Lowy Cancer Research Centre and Prince of Wales Clinical School; UNSW Australia; Sydney New South Wales Australia
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