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Rofes P, González S, Navarro M, Moreno-Cabrera JM, Solanes A, Darder E, Carrasco E, Iglesias S, Salinas M, Gómez C, Velasco À, Tuset N, Varela M, Llort G, Ramon Y Cajal T, Grau È, Dueñas N, de la Ossa Merlano N, Matías-Guiu X, Rivera B, Balmaña J, Pineda M, Brunet J, Capellá G, Del Valle J, Lázaro C. Paired Somatic-Germline Testing of 15 Polyposis and Colorectal Cancer-Predisposing Genes Highlights the Role of APC Mosaicism in de Novo Familial Adenomatous Polyposis. J Mol Diagn 2021; 23:1452-1459. [PMID: 34454113 DOI: 10.1016/j.jmoldx.2021.07.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 07/02/2021] [Accepted: 07/21/2021] [Indexed: 11/28/2022] Open
Abstract
Familial adenomatous polyposis (FAP) is an autosomal dominant syndrome responsible for 1% of colorectal cancers (CRCs). Up to 90% of classic FAPs are caused by inactivating mutations in APC, and mosaicism has been previously reported in 20% of de novo cases, usually linked to milder phenotypic manifestations. This study aimed to explore the prevalence of mosaicism in 11 unsolved cases of classic FAP and to evaluate the diagnostic yield of somatic testing. Paired samples of colorectal polyps, tumors, and/or mucosa were analyzed using a custom next-generation sequencing panel targeting 15 polyposis and CRC-predisposing genes. Whenever possible, the extension of mosaicism to blood or sperm was also examined. Of 11 patients with classic adenomatous polyposis, a mosaic pathogenic variant in APC was identified in 7 (64%). No other altered genes were identified. In two of seven patients (29%), mosaicism was found restricted to colonic tissues, whereas in five of seven patients (71%), it was extended to the blood. Germline affectation was confirmed in one patient. We report the first analysis at a somatic level of 15 genes associated with CRC susceptibility, which highlights the role of APC mosaicism in classic FAP etiology. The results further reinforce the importance of testing target tissues when blood test results are negative.
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Affiliation(s)
- Paula Rofes
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain
| | - Sara González
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain
| | - Matilde Navarro
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain; Hereditary Cancer Program, Program for Predictive and Personalized Medicine of Cancer-Germans Trias i Pujol Research Institute (PMPPC-IGTP), Badalona, Spain
| | - José Marcos Moreno-Cabrera
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain; Hereditary Cancer Program, Program for Predictive and Personalized Medicine of Cancer-Germans Trias i Pujol Research Institute (PMPPC-IGTP), Badalona, Spain
| | - Ares Solanes
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain; Hereditary Cancer Program, Program for Predictive and Personalized Medicine of Cancer-Germans Trias i Pujol Research Institute (PMPPC-IGTP), Badalona, Spain
| | - Esther Darder
- Hereditary Cancer Program, Catalan Institute of Oncology, Girona Institute for Biomedical Research (IDIBGi), Girona, Spain
| | - Estela Carrasco
- Hereditary Cancer Genetics Group, Vall d'Hebron Institute of Oncology (VHIO), Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Sílvia Iglesias
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain
| | - Mónica Salinas
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain
| | - Carolina Gómez
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain
| | - Àngela Velasco
- Hereditary Cancer Program, Catalan Institute of Oncology, Girona Institute for Biomedical Research (IDIBGi), Girona, Spain
| | - Noemí Tuset
- Medical Oncology Department, Arnau de Vilanova University Hospital, Lleida, Spain
| | - Mar Varela
- Department of Pathology, Bellvitge University Hospital, Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain
| | - Gemma Llort
- Medical Oncology Department, Parc Taulí University Hospital, Sabadell, Spain
| | | | - Èlia Grau
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain; Hereditary Cancer Program, Program for Predictive and Personalized Medicine of Cancer-Germans Trias i Pujol Research Institute (PMPPC-IGTP), Badalona, Spain
| | - Núria Dueñas
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain
| | - Napoleón de la Ossa Merlano
- Department of Pathology, General University Hospital of Catalonia, QuironSalud Group, Sant Cugat del Vallès, Spain
| | - Xavier Matías-Guiu
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain; Department of Pathology, Bellvitge University Hospital, IDIBELL, University of Barcelona, Barcelona, Spain; Department of Pathology, Arnau de Vilanova University Hospital, Lleida Institute for Biomedical Research (IRBLleida), University of Lleida, Lleida, Spain
| | - Bárbara Rivera
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain; Gerald Bronfman Department of Oncology, McGill University, Montreal, Quebec, Canada
| | - Judith Balmaña
- Hereditary Cancer Genetics Group, Vall d'Hebron Institute of Oncology (VHIO), Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain
| | - Marta Pineda
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain
| | - Joan Brunet
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain; Hereditary Cancer Program, Catalan Institute of Oncology, Girona Institute for Biomedical Research (IDIBGi), Girona, Spain
| | - Gabriel Capellá
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain
| | - Jesús Del Valle
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain
| | - Conxi Lázaro
- Hereditary Cancer Program, Program in Molecular Mechanisms and Experimental Therapy in Oncology (Oncobell), Bellvitge Institute for Biomedical Research (IDIBELL), Catalan Institute of Oncology, l'Hospitalet del Llobregat, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Madrid, Spain.
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Cai D, He F, Xu X, Xiong F, Zhang L. APC c.4621C>T variant causing Gardner's syndrome in a Han Chinese family may be inherited through maternal mosaicism. Exp Ther Med 2021; 21:488. [PMID: 33790997 PMCID: PMC8005673 DOI: 10.3892/etm.2021.9919] [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: 06/20/2020] [Accepted: 10/15/2020] [Indexed: 12/03/2022] Open
Abstract
Gardner's syndrome is a rare autosomal dominant hereditary disease that is characterized by multiple colorectal polyps combined with extra-colonic presentation (such as osteoma or desmoid tumors) of familial adenomatous polyposis syndrome. Gardner's syndrome is caused by the mutation of the adenomatous polyposis coli (APC) gene, which is located at 5q21. The aim of the current study was to investigate the APC gene mutations present in a Han Chinese family diagnosed with Gardner's syndrome. The 38-year-old proband presented with clinical symptoms, and was later diagnosed with Gardner's syndrome. Genomic DNA was extracted from the peripheral venous blood of 150 normal controls as well as the family members of the proband. Analysis of the respective APC gene sequences was performed using PCR amplification and Sanger sequencing. Pathogenesis associated with the APC mutation was investigated using reverse-transcription quantitative PCR and determined through bioinformatics approaches. Haplotype analysis was performed to identify the genetic source of the mutation(s). In the initial screening for APC variants, the APC c.4621C>T variant was detected in the proband and his son, but was not detected in the proband's affected mother. The mRNA expression changed significantly according to age and the presence of the mutation in the blood of the patients. Haplotype analysis suggested the presence of maternal mosaicism for this mutation. Haplotype analysis revealed that the APC c.4621C>T variant in a patient with Gardner's syndrome was most likely derived from his mother through mosaicism. These results indicate the necessity to verify the possibility of gonadal mosaicism when a proband diagnosed with Gardner's syndrome appears to exhibit a de novo mutation.
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Affiliation(s)
- Decheng Cai
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Fei He
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Xiangmin Xu
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China.,Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Fu Xiong
- Department of Medical Genetics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China.,Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Leitao Zhang
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
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Jansen AML, Goel A. Mosaicism in Patients With Colorectal Cancer or Polyposis Syndromes: A Systematic Review. Clin Gastroenterol Hepatol 2020; 18:1949-1960. [PMID: 32147591 PMCID: PMC7725418 DOI: 10.1016/j.cgh.2020.02.049] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 02/09/2020] [Accepted: 02/14/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS Somatic mosaicism, in which variants arise post-zygotically and are therefore not present in all cells in the body, may be an underestimated cause of colorectal cancer (CRC) and polyposis syndromes. We performed a systematic review to provide a comprehensive overview of somatic mosaicism in patients with CRC and polyposis syndromes. METHODS We searched PubMed through March 2018 to identify reports of mosaicism in patients with CRC or polyposis syndromes. We divided the final set of studies into 3 subgroups describing APC mosaicism, mosaicism in other CRC susceptibility genes, and epigenetic mosaicism. RESULTS Of the 232 articles identified in our systematic search, 46 met the criteria for further analysis. Of these, 35 studies described mosaic variants or epimutations in patients with CRC or polyposis syndromes. Nineteen studies described APC mosaicism, comprising a total of 57 patients. Six described mosaicism in genes associated with familial CRC syndromes, such as Lynch and Cowden syndromes. Ten studies described epigenetic mosaicism, sometimes resulting from a germline variant (such as deletion of EPCAM). CONCLUSIONS We found that somatic mosaicism is underdiagnosed but critical for determining the clinical management of patients with de novo polyposis who possibly carry mosaic APC variants, and present a decision tree for the clinical management of these patients. Mosaicism in genes associated with susceptibility to CRC contributes to development of other familial CRC syndromes. Heritable epigenetic mosaicism is likely underestimated and could have a dominant pattern of inheritance. However, the inheritance of primary mosaic epimutations, without an underlying genetic cause, is complex and not fully understood.
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Affiliation(s)
- Anne Maria Lucia Jansen
- Center for Gastrointestinal Research, Center for Translational Genomics and Oncology, Baylor Scott & White Research Institute and Charles A. Sammons Cancer Center, Dallas, Texas
| | - Ajay Goel
- Center for Gastrointestinal Research, Center for Translational Genomics and Oncology, Baylor Scott & White Research Institute and Charles A. Sammons Cancer Center, Dallas, Texas; Department of Molecular Diagnostics and Experimental Therapeutics, Beckman Research Institute of City of Hope, Duarte, California.
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Spier I, Drichel D, Kerick M, Kirfel J, Horpaopan S, Laner A, Holzapfel S, Peters S, Adam R, Zhao B, Becker T, Lifton RP, Perner S, Hoffmann P, Kristiansen G, Timmermann B, Nöthen MM, Holinski-Feder E, Schweiger MR, Aretz S. Low-level APC mutational mosaicism is the underlying cause in a substantial fraction of unexplained colorectal adenomatous polyposis cases. J Med Genet 2015; 53:172-9. [PMID: 26613750 DOI: 10.1136/jmedgenet-2015-103468] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 10/22/2015] [Indexed: 12/20/2022]
Abstract
BACKGROUND In 30-50% of patients with colorectal adenomatous polyposis, no germline mutation in the known genes APC, causing familial adenomatous polyposis, MUTYH, causing MUTYH-associated polyposis, or POLE or POLD1, causing polymerase-proofreading-associated polyposis can be identified, although a hereditary aetiology is likely. This study aimed to explore the impact of APC mutational mosaicism in unexplained polyposis. METHODS To comprehensively screen for somatic low-level APC mosaicism, high-coverage next-generation sequencing of the APC gene was performed using DNA from leucocytes and a total of 53 colorectal tumours from 20 unrelated patients with unexplained sporadic adenomatous polyposis. APC mosaicism was assumed if the same loss-of-function APC mutation was present in ≥ 2 anatomically separated colorectal adenomas/carcinomas per patient. All mutations were validated using diverse methods. RESULTS In 25% (5/20) of patients, somatic mosaicism of a pathogenic APC mutation was identified as underlying cause of the disease. In 2/5 cases, the mosaic level in leucocyte DNA was slightly below the sensitivity threshold of Sanger sequencing; while in 3/5 cases, the allelic fraction was either very low (0.1-1%) or no mutations were detectable. The majority of mosaic mutations were located outside the somatic mutation cluster region of the gene. CONCLUSIONS The present data indicate a high prevalence of pathogenic mosaic APC mutations below the detection thresholds of routine diagnostics in adenomatous polyposis, even if high-coverage sequencing of leucocyte DNA alone is taken into account. This has important implications for both routine work-up and strategies to identify new causative genes in this patient group.
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Affiliation(s)
- Isabel Spier
- Institute of Human Genetics, University of Bonn, Bonn, Germany Center for Hereditary Tumor Syndromes, University of Bonn, Bonn, Germany
| | - Dmitriy Drichel
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Martin Kerick
- Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, Berlin, Germany Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
| | - Jutta Kirfel
- Center for Hereditary Tumor Syndromes, University of Bonn, Bonn, Germany Institute of Pathology, University of Bonn, Bonn, Germany
| | - Sukanya Horpaopan
- Institute of Human Genetics, University of Bonn, Bonn, Germany Department of Anatomy, Faculty of Medical Science, Naresuan University, Phitsanulok, Thailand
| | - Andreas Laner
- Medizinische Klinik-Campus Innenstadt, Klinikum der LMU, Munich, Germany MGZ-Center of Medical Genetics, Munich, Germany
| | - Stefanie Holzapfel
- Institute of Human Genetics, University of Bonn, Bonn, Germany Center for Hereditary Tumor Syndromes, University of Bonn, Bonn, Germany
| | - Sophia Peters
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - Ronja Adam
- Institute of Human Genetics, University of Bonn, Bonn, Germany Center for Hereditary Tumor Syndromes, University of Bonn, Bonn, Germany
| | - Bixiao Zhao
- Departments of Genetics, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Tim Becker
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany Institute of Medical Biometry, Informatics, and Epidemiology, University of Bonn, Bonn, Germany
| | - Richard P Lifton
- Departments of Genetics, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Sven Perner
- Section for Prostate Cancer Research, Institute of Pathology, Center for Integrated Oncology Cologne/Bonn, University Hospital of Bonn, Bonn, Germany
| | - Per Hoffmann
- Institute of Human Genetics, University of Bonn, Bonn, Germany Department of Genomics, Life & Brain Center, University of Bonn, Bonn, Germany Division of Medical Genetics, University Hospital Basel and Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Glen Kristiansen
- Center for Hereditary Tumor Syndromes, University of Bonn, Bonn, Germany Institute of Pathology, University of Bonn, Bonn, Germany
| | - Bernd Timmermann
- Next Generation Sequencing Group, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Markus M Nöthen
- Institute of Human Genetics, University of Bonn, Bonn, Germany Department of Genomics, Life & Brain Center, University of Bonn, Bonn, Germany
| | - Elke Holinski-Feder
- Medizinische Klinik-Campus Innenstadt, Klinikum der LMU, Munich, Germany MGZ-Center of Medical Genetics, Munich, Germany
| | - Michal R Schweiger
- Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, Berlin, Germany Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
| | - Stefan Aretz
- Institute of Human Genetics, University of Bonn, Bonn, Germany Center for Hereditary Tumor Syndromes, University of Bonn, Bonn, Germany
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