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Burgess JT, Rose M, Boucher D, Plowman J, Molloy C, Fisher M, O'Leary C, Richard DJ, O'Byrne KJ, Bolderson E. The Therapeutic Potential of DNA Damage Repair Pathways and Genomic Stability in Lung Cancer. Front Oncol 2020; 10:1256. [PMID: 32850380 PMCID: PMC7399071 DOI: 10.3389/fonc.2020.01256] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/17/2020] [Indexed: 12/16/2022] Open
Abstract
Despite advances in our understanding of the molecular biology of the disease and improved therapeutics, lung cancer remains the most common cause of cancer-related deaths worldwide. Therefore, an unmet need remains for improved treatments, especially in advanced stage disease. Genomic instability is a universal hallmark of all cancers. Many of the most commonly prescribed chemotherapeutics, including platinum-based compounds such as cisplatin, target the characteristic genomic instability of tumors by directly damaging the DNA. Chemotherapies are designed to selectively target rapidly dividing cells, where they cause critical DNA damage and subsequent cell death (1, 2). Despite the initial efficacy of these drugs, the development of chemotherapy resistant tumors remains the primary concern for treatment of all lung cancer patients. The correct functioning of the DNA damage repair machinery is essential to ensure the maintenance of normal cycling cells. Dysregulation of these pathways promotes the accumulation of mutations which increase the potential of malignancy. Following the development of the initial malignancy, the continued disruption of the DNA repair machinery may result in the further progression of metastatic disease. Lung cancer is recognized as one of the most genomically unstable cancers (3). In this review, we present an overview of the DNA damage repair pathways and their contributions to lung cancer disease occurrence and progression. We conclude with an overview of current targeted lung cancer treatments and their evolution toward combination therapies, including chemotherapy with immunotherapies and antibody-drug conjugates and the mechanisms by which they target DNA damage repair pathways.
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Affiliation(s)
- Joshua T Burgess
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Maddison Rose
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Didier Boucher
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Jennifer Plowman
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Christopher Molloy
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Mark Fisher
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Connor O'Leary
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia.,Princess Alexandra Hospital, Brisbane, QLD, Australia
| | - Derek J Richard
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Kenneth J O'Byrne
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia.,Princess Alexandra Hospital, Brisbane, QLD, Australia
| | - Emma Bolderson
- Cancer & Ageing Research Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation at the Translational Research Institute (TRI), Queensland University of Technology (QUT), Brisbane, QLD, Australia.,Princess Alexandra Hospital, Brisbane, QLD, Australia
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2
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Torabi K, Erola P, Alvarez-Mora MI, Díaz-Gay M, Ferrer Q, Castells A, Castellví-Bel S, Milà M, Lozano JJ, Miró R, Ried T, Ponsa I, Camps J. Quantitative analysis of somatically acquired and constitutive uniparental disomy in gastrointestinal cancers. Int J Cancer 2018; 144:513-524. [PMID: 30350313 PMCID: PMC6635747 DOI: 10.1002/ijc.31936] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 08/31/2018] [Accepted: 10/02/2018] [Indexed: 12/20/2022]
Abstract
Somatically acquired uniparental disomies (aUPDs) are frequent events in solid tumors and have been associated with cancer‐related genes. Studies assessing their functional consequences across several cancer types are therefore necessary. Here, we aimed at integrating aUPD profiles with the mutational status of cancer‐related genes in a tumor‐type specific manner. Using TCGA datasets for 1,032 gastrointestinal cancers, including colon (COAD), rectum (READ), stomach (STAD), esophageal adenocarcinoma (EAC) and esophageal squamous cell carcinoma (ESCC), we show a non‐random distribution of aUPD, suggesting the existence of a cancer‐specific landscape of aUPD events. Our analysis indicates that aUPD acts as a “second hit” in Knudson's model in order to achieve biallelic inactivation of tumor suppressor genes. In particular, APC, ARID1A and NOTCH1 were recurrently inactivated by the presence of homozygous mutation as a consequence of aUPD in COAD and READ, STAD and ESCC, respectively. Furthermore, while TP53 showed inactivation caused by aUPD at chromosome arm 17p across all tumor types, copy number losses at this genomic position were also frequent. By experimental and computationally inferring genome ploidy, we demonstrate that an increased number of aUPD events, both affecting the whole chromosome or segments of it, were present in highly aneuploid genomes compared to near‐diploid tumors. Finally, the presence of mosaic UPD was detected at a higher frequency in DNA extracted from peripheral blood lymphocytes of patients with colorectal cancer compared to healthy individuals. In summary, our study defines specific profiles of aUPD in gastrointestinal cancers and provides unequivocal evidence of their relevance in cancer. What's new? Somatically acquired uniparental disomies (aUPDs), in which two copies of a chromosome originate from the same parent, have been documented in various human cancers. Here, the authors examined the frequency of aUPDs in different gastrointestinal cancer types. Events involving aUPDs were found to occur at high incidence in gastrointestinal cancers and at increased frequency particularly in highly aneuploid genomes. The data also reveal a nonrandom distribution of aUPDs, with evidence of biallelic inactivation of tumor suppressor genes and activation of oncogenes in a tumor type‐specific manner. The findings suggest that aUPDs are functionally relevant in gastrointestinal malignancies.
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Affiliation(s)
- Keyvan Torabi
- Gastrointestinal and Pancreatic Oncology Group, Institut D'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Catalonia, Spain.,Unitat de Biologia Cel·lular i Genètica Mèdica, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia, Spain
| | - Pau Erola
- Bioinformatics Unit, CIBEREHD, Barcelona, Catalonia, Spain.,Roslin Institute, University of Edinburgh, Midlothian, Scotland, United Kingdom
| | - Maria Isabel Alvarez-Mora
- Biochemistry and Molecular Genetics Department, Hospital Clínic, IDIBAPS, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona, Catalonia, Spain
| | - Marcos Díaz-Gay
- Gastrointestinal and Pancreatic Oncology Group, Institut D'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Catalonia, Spain
| | - Queralt Ferrer
- Gastrointestinal and Pancreatic Oncology Group, Institut D'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Catalonia, Spain
| | - Antoni Castells
- Gastrointestinal and Pancreatic Oncology Group, Institut D'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Catalonia, Spain
| | - Sergi Castellví-Bel
- Gastrointestinal and Pancreatic Oncology Group, Institut D'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Catalonia, Spain
| | - Montserrat Milà
- Biochemistry and Molecular Genetics Department, Hospital Clínic, IDIBAPS, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Barcelona, Catalonia, Spain
| | | | - Rosa Miró
- Unitat de Biologia Cel·lular i Genètica Mèdica, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia, Spain.,Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia, Spain
| | - Thomas Ried
- Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Immaculada Ponsa
- Unitat de Biologia Cel·lular i Genètica Mèdica, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia, Spain.,Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia, Spain
| | - Jordi Camps
- Gastrointestinal and Pancreatic Oncology Group, Institut D'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), Barcelona, Catalonia, Spain.,Unitat de Biologia Cel·lular i Genètica Mèdica, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia, Spain
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3
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Eizuka M, Sugai T, Habano W, Uesugi N, Takahashi Y, Kawasaki K, Yamamoto E, Suzuki H, Matsumoto T. Molecular alterations in colorectal adenomas and intramucosal adenocarcinomas defined by high-density single-nucleotide polymorphism arrays. J Gastroenterol 2017; 52:1158-1168. [PMID: 28197804 PMCID: PMC5666076 DOI: 10.1007/s00535-017-1317-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 01/30/2017] [Indexed: 02/04/2023]
Abstract
BACKGROUND We examined colorectal adenomas and intramucosal adenocarcinomas (IMAs) to develop a genome-wide overview of copy number alterations (CNAs) during colorectal tumorigenesis. METHODS We analysed CNAs using a high-resolution SNP array of isolated tumour glands obtained from 55 colorectal adenomas (35 low-grade adenomas and 20 high-grade adenomas) and 30 IMAs. Next, we examined whether frequent CNAs differed between low-grade and high-grade adenomas or high-grade adenomas and IMAs. Finally, we investigated the total lengths of the CNAs in low-grade adenomas, high-grade adenomas, and IMAs. RESULTS Although no frequent CNAs were found in low-grade adenomas, the most frequent alterations of high-grade adenomas were gains of 7q11, 7q21 and 9p13 and loss of 5q14.3-35. High levels of gains were detected at 13q, 7q, 8p, 20q, 7p, 18p and 17p in IMAs. Although no frequent alteration differed between low-grade and high-grade adenomas, significant differences of gains at 13q, 17p and 18p were found between high-grade adenoma and IMAs. Although the total lengths of all CNAs (gains and losses), copy number gains, and losses of heterozygosity were significantly greater in high-grade adenomas than in low-grade adenomas, no significant differences in the lengths of CNAs were found between high-grade adenomas and IMAs. CONCLUSIONS Genomic alterations play an essential role in early colorectal carcinogenesis. CNAs in colorectal tumours provide new insights for evaluation of colorectal tumorigenesis.
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Affiliation(s)
- Makoto Eizuka
- Department of Molecular Diagnostic Pathology, School of Medicine, Iwate Medical University, 19-1, Uchimaru, Morioka, 020-8505 Japan
| | - Tamotsu Sugai
- Department of Molecular Diagnostic Pathology, School of Medicine, Iwate Medical University, 19-1, Uchimaru, Morioka, 020-8505 Japan
| | - Wataru Habano
- Department of Pharmacodynamics and Molecular Genetics, School of Pharmacy, Iwate Medical University, Morioka, Japan
| | - Noriyuki Uesugi
- Department of Molecular Diagnostic Pathology, School of Medicine, Iwate Medical University, 19-1, Uchimaru, Morioka, 020-8505 Japan
| | - Yayoi Takahashi
- Department of Molecular Diagnostic Pathology, School of Medicine, Iwate Medical University, 19-1, Uchimaru, Morioka, 020-8505 Japan
| | - Keisuke Kawasaki
- Division of Gastroenterology, Department of Internal Medicine, Iwate Medical University, Morioka, Japan
| | - Eiichiro Yamamoto
- Department of Molecular Biology, School of Medicine, Sapporo Medical University, Sapporo, Japan
| | - Hiromu Suzuki
- Department of Molecular Biology, School of Medicine, Sapporo Medical University, Sapporo, Japan
| | - Takayuki Matsumoto
- Division of Gastroenterology, Department of Internal Medicine, Iwate Medical University, Morioka, Japan
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4
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DNA copy number profiling in microsatellite-stable and microsatellite-unstable hereditary non-polyposis colorectal cancers by targeted CNV array. Funct Integr Genomics 2016; 17:85-96. [DOI: 10.1007/s10142-016-0532-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/08/2016] [Accepted: 04/18/2016] [Indexed: 01/19/2023]
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5
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Abstract
Fordyce spots are a frequent condition under which sebaceous glands are found in the oral mucosa. There are 2 studies in the literature that have found an association between Fordyce spots and either Muir-Torre syndrome or Lynch syndrome. Despite this, no study on the expression of mismatch repair (MMR) proteins has been performed on biopsies of Fordyce granules. In this study, we intend to study the expression of MMR proteins under Fordyce condition. We investigated 9 cases of Fordyce spots of the oral mucosa from 6 men and 3 women, using immunohistochemistry with antibodies for the MutS protein homolog 6 (MSH6), MutS protein homolog 2 (MSH2), MutL protein homolog 1 (MLH1), and postmeiotic segregation increased 2 (PMS2). All cases showed the preservation of the expression of all markers. Even though a strong association has been demonstrated between Lynch syndrome and Fordyce spots, our study suggests that studying the biopsies of Fordyce condition by immunohistochemistry for MMR proteins might not be necessary.
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6
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Torabi K, Miró R, Fernández-Jiménez N, Quintanilla I, Ramos L, Prat E, del Rey J, Pujol N, Killian JK, Meltzer PS, Fernández PL, Ried T, Lozano JJ, Camps J, Ponsa I. Patterns of somatic uniparental disomy identify novel tumor suppressor genes in colorectal cancer. Carcinogenesis 2015; 36:1103-10. [PMID: 26243311 PMCID: PMC4598814 DOI: 10.1093/carcin/bgv115] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 07/06/2015] [Accepted: 07/29/2015] [Indexed: 01/17/2023] Open
Abstract
Colorectal cancer (CRC) is characterized by specific patterns of copy number alterations (CNAs), which helped with the identification of driver oncogenes and tumor suppressor genes (TSGs). More recently, the usage of single nucleotide polymorphism arrays provided information of copy number neutral loss of heterozygosity, thus suggesting the occurrence of somatic uniparental disomy (UPD) and uniparental polysomy (UPP) events. The aim of this study is to establish an integrative profiling of recurrent UPDs/UPPs and CNAs in sporadic CRC. Our results indicate that regions showing high frequencies of UPD/UPP mostly coincide with regions typically involved in genomic losses. Among them, chromosome arms 3p, 5q, 9q, 10q, 14q, 17p, 17q, 20p, 21q and 22q preferentially showed UPDs/UPPs over genomic losses suggesting that tumor cells must maintain the disomic state of certain genes to favor cellular fitness. A meta-analysis using over 300 samples from The Cancer Genome Atlas confirmed our findings. Several regions affected by recurrent UPDs/UPPs contain well-known TSGs, as well as novel candidates such as ARID1A, DLC1, TCF7L2 and DMBT1. In addition, VCAN, FLT4, SFRP1 and GAS7 were also frequently involved in regions of UPD/UPP and displayed high levels of methylation. Finally, sequencing and fluorescence in situ hybridization analysis of the gene APC underlined that a somatic UPD event might represent the second hit to achieve biallelic inactivation of this TSG in colorectal tumors. In summary, our data define a profile of somatic UPDs/UPPs in sporadic CRC and highlights the importance of these events as a mechanism to achieve the inactivation of TSGs.
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Affiliation(s)
- Keyvan Torabi
- Unitat de Biologia Cellular i Genètica Mèdica, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain
| | - Rosa Miró
- Unitat de Biologia Cellular i Genètica Mèdica, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain
| | - Nora Fernández-Jiménez
- Unitat de Biologia Cellular i Genètica Mèdica, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain, Present address: Epigenetics Group, International Agency for Research on Cancer 69008, Lyon, France
| | - Isabel Quintanilla
- Gastrointestinal and Pancreatic Oncology Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Catalonia 08036, Spain
| | - Laia Ramos
- Unitat de Biologia Cellular i Genètica Mèdica, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain, Present address: Unitat de Genòmica i Bioinformàtica, Institut de Medicina Predictiva i Personalitzada del Càncer (IMPPC), Badalona, Catalonia 08916, Spain
| | - Esther Prat
- Unitat de Biologia Cellular i Genètica Mèdica, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain, Present address: Laboratori de Genètica Molecular, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospitalet de Llobregat, Catalonia 08908, Spain
| | - Javier del Rey
- Unitat de Biologia Cellular i Genètica Mèdica, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain
| | - Núria Pujol
- Unitat de Biologia Cellular i Genètica Mèdica, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain
| | - J Keith Killian
- Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Paul S Meltzer
- Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Pedro Luis Fernández
- Department of Pathology, Hospital Clínic/IDIBAPS, Universitat de Barcelona, Barcelona, Catalonia 08036, Spain and
| | - Thomas Ried
- Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Juan José Lozano
- Bioinformatics Unit, CIBERehd, Barcelona, Catalonia 08036, Spain
| | - Jordi Camps
- Unitat de Biologia Cellular i Genètica Mèdica, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain, Gastrointestinal and Pancreatic Oncology Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Barcelona, Catalonia 08036, Spain, Genetics Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Immaculada Ponsa
- Unitat de Biologia Cellular i Genètica Mèdica, Departament de Biologia Cellular, Fisiologia i Immunologia, Facultat de Medicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain, Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Bellaterra, Catalonia 08193, Spain,
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7
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Geurts-Giele WRR, Leenen CHM, Dubbink HJ, Meijssen IC, Post E, Sleddens HFBM, Kuipers EJ, Goverde A, van den Ouweland AMW, van Lier MGF, Steyerberg EW, van Leerdam ME, Wagner A, Dinjens WNM. Somatic aberrations of mismatch repair genes as a cause of microsatellite-unstable cancers. J Pathol 2014; 234:548-59. [PMID: 25111426 DOI: 10.1002/path.4419] [Citation(s) in RCA: 118] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 07/28/2014] [Accepted: 08/06/2014] [Indexed: 12/17/2022]
Abstract
Lynch syndrome (LS) is caused by germline mutations in mismatch repair (MMR) genes, resulting in microsatellite-unstable tumours. Approximately 35% of suspected LS (sLS) patients test negative for germline MMR gene mutations, hampering conclusive LS diagnosis. The aim of this study was to investigate somatic MMR gene aberrations in microsatellite-unstable colorectal and endometrial cancers of sLS patients negative for germline MMR gene mutations. Suspected LS cases were selected from a retrospective Clinical Genetics Department diagnostic cohort and from a prospective multicentre population-based study on LS in The Netherlands. In total, microsatellite-unstable tumours of 40 sLS patients (male/female 20/20, median age 57 years) were screened for somatic MMR gene mutations by next-generation sequencing. In addition, loss of heterozygosity (LOH) of the affected MMR genes in these tumours as well as in 68 LS-associated tumours and 27 microsatellite-unstable tumours with MLH1 promoter hypermethylation was studied. Of the sLS cases, 5/40 (13%) tumours had two pathogenic somatic mutations and 16/40 (40%) tumours had a (likely) pathogenic mutation and LOH. Overall, LOH of the affected MMR gene locus was observed in 24/39 (62%) tumours with informative LOH markers. Of the LS cases and the tumours with MLH1 promoter hypermethylation, 39/61 (64%) and 2/21 (10%) tumours, respectively, demonstrated LOH. Half of microsatellite-unstable tumours of sLS patients without germline MMR gene mutations had two (likely) deleterious somatic MMR gene aberrations, indicating their sporadic origin. Therefore, we advocate adding somatic mutation and LOH analysis of the MMR genes to the molecular diagnostic workflow of LS.
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Affiliation(s)
- Willemina R R Geurts-Giele
- Department of Pathology, Erasmus MC Cancer Institute, University Medical Centre, Rotterdam, The Netherlands
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8
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Pineda M, González-Acosta M, Thompson BA, Sánchez R, Gómez C, Martínez-López J, Perea J, Caldés T, Rodríguez Y, Landolfi S, Balmaña J, Lázaro C, Robles L, Capellá G, Rueda D. Detailed characterization of MLH1 p.D41H and p.N710D variants coexisting in a Lynch syndrome family with conserved MLH1 expression tumors. Clin Genet 2014; 87:543-8. [PMID: 25060679 DOI: 10.1111/cge.12467] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 07/18/2014] [Accepted: 07/22/2014] [Indexed: 12/26/2022]
Abstract
Lynch syndrome (LS) is an autosomal dominant cancer-susceptibility disease caused by inactivating germline mutations in mismatch repair (MMR) genes. Variants of unknown significance (VUS) are often detected in mutational analysis of MMR genes. Here we describe a large family fulfilling Amsterdam I criteria carrying two rare VUS in the MLH1 gene: c.121G > C (p.D41H) and c.2128A > G (p.N710D). Collection of clinico-pathological data, multifactorial analysis, in silico predictions, and functional analyses were used to elucidate the clinical significance of the identified MLH1 VUS. Only the c.121G > C variant cosegregated with LS-associated tumors in the family. Diagnosed colorectal tumors were microsatellite unstable although immunohistochemical staining revealed no loss of MMR proteins expression. Multifactorial likelihood analysis classified c.2128A > G as a non-pathogenic variant and c.121G > C as pathogenic. In vitro functional tests revealed impaired MMR activity and diminished expression of c.121G > C. Accordingly, the N710 residue is located in the unconserved MLH1 C-terminal domain, whereas D41 is highly conserved and located in the ATPase domain. The obtained results will enable adequate genetic counseling of c.121G > C and c.2128A > G variant carriers and their families. Furthermore, they exemplify how cumulative data and comprehensive analyses are mandatory to refine the classification of MMR variants.
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Affiliation(s)
- M Pineda
- Hereditary Cancer Program, Catalan Institute of Oncology, ICO-IDIBELL, Hospitalet de Llobregat, Barcelona, Spain
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9
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Li M, Zhang Q, Liu L, Lu W, Wei H, Li RW, Lu S. Expression of the mismatch repair gene hMLH1 is enhanced in non-small cell lung cancer with EGFR mutations. PLoS One 2013; 8:e78500. [PMID: 24205245 PMCID: PMC3812034 DOI: 10.1371/journal.pone.0078500] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 09/13/2013] [Indexed: 11/19/2022] Open
Abstract
Mismatch repair (MMR) plays a pivotal role in keeping the genome stable. MMR dysfunction can lead to carcinogenesis by gene mutation accumulation. HMSH2 and hMLH1 are two key components of MMR. High or low expression of them often mark the status of MMR function. Mutations (EGFR, KRAS, etc) are common in non-small cell lung cancer (NSCLC). However, it is not clear what role MMR plays in NSCLC gene mutations. The expression of MMR proteins hMSH2 and hMLH1, and the proliferation markers PCNA and Ki67 were measured by immunohistochemistry in 181 NSCLCs. EGFR and KRAS mutations were identified by high resolution melting analysis. Stronger hMLH1 expression correlated to a higher frequency of EGFR mutations in exon 19 and 21 (p<0.0005). Overexpression of hMLH1 and the adenocarcinoma subtype were both independent factors that related to EGFR mutations in NSCLCs (p=0.013 and p<0.0005). The expression of hMLH1, hMSH2 and PCNA increased, while Ki67 expression significantly decreased (p=0.030) in NSCLCs with EGFR mutations. Overexpression of hMLH1 could be a new molecular marker to predict the response to EGFR-TKIs in NSCLCs. Furthermore, EGFR mutations might be an early event of NSCLC that occur before MMR dysfunction.
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Affiliation(s)
- Mei Li
- Central Laboratory, The Second Hospital of Dalian Medical University, Dalian, PR China
| | - Qiuping Zhang
- Department of Pathology, The First Hospital of Dalian Medical University, Dalian, PR China
| | - Lina Liu
- Department of Internal Medicine, The First Hospital of Dalian Medical University, Dalian, PR China
| | - Weipeng Lu
- Central Laboratory, The Second Hospital of Dalian Medical University, Dalian, PR China
| | - Hong Wei
- Central Laboratory, The Second Hospital of Dalian Medical University, Dalian, PR China
| | - Rachel W. Li
- The Medical School, The Australian Medical University, Canberra, Australia
| | - Shen Lu
- Central Laboratory, The Second Hospital of Dalian Medical University, Dalian, PR China
- * E-mail:
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10
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Spaepen M, Neven E, Sagaert X, De Hertogh G, Beert E, Wimmer K, Matthijs G, Legius E, Brems H. EPCAM germline and somatic rearrangements in Lynch syndrome: identification of a novel 3'EPCAM deletion. Genes Chromosomes Cancer 2013; 52:845-54. [PMID: 23801599 DOI: 10.1002/gcc.22080] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 05/15/2013] [Accepted: 05/16/2013] [Indexed: 11/07/2022] Open
Abstract
3'EPCAM (Epithelial Cell Adhesion Molecule) genomic rearrangements can be a cause of mismatch repair deficiency in rare Lynch syndrome families. 3'EPCAM deletions include the polyadenylation signal and might result in promoter hypermethylation of the centromeric MSH2 gene in cis. A somatic rearrangement in trans affecting MSH2 is responsible for the final mismatch repair deficiency in the corresponding tumors but the mechanisms are not well documented. In this report two germline 3'EPCAM deletions are described together with the corresponding somatic mutations in the patient's colorectal tumors. Mutation and breakpoint analysis resulted in the identification of one novel (c.556-531_*872del) and one known EPCAM deletion (c.859-689_*14697del). Both deletions resulted from Alu mediated homologous recombination causing aberrant EPCAM-MSH2 fusion transcripts. The colorectal tumors of the deletion carriers were MSI-high. Strong hypermethylation of the MSH2 promoter was measured. Analysis of somatic genomic rearrangements showed a 4 Mb deletion including the EPCAM, MSH2 and MSH6 genes in one tumor and copy neutral loss of heterozygosity in the EPCAM-MSH2 region in the other tumor. This indicates that hemi- and homozygous hypermethylation of the MSH2 promoter and hence complete silencing of MSH2 expression was responsible for the mismatch repair deficiency in both colorectal tumors.
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Affiliation(s)
- Marijke Spaepen
- Department of Human Genetics, University Hospital Leuven, 3000 Leuven, Belgium.
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11
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Yam YY, Hoh BP, Othman NH, Hassan S, Yahya MM, Zakaria Z, Ankathil R. Somatic copy-neutral loss of heterozygosity and copy number abnormalities in Malaysian sporadic colorectal carcinoma patients. GENETICS AND MOLECULAR RESEARCH 2013; 12:319-27. [PMID: 23420356 DOI: 10.4238/2013.february.7.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Colorectal cancer is one of the most common cancers in many countries, including Malaysia. The accumulation of genomic alterations is an important feature of colorectal carcinogenesis. A better understanding of the molecular events underlying the stages of colorectal carcinogenesis might be helpful in the detection and management of the disease. We used a commercially available single-nucleotide polymorphism genotyping array to detect both copy number abnormalities (CNAs) and copy-neutral loss of heterozygosity (LOH) in sporadic colorectal carcinomas. Matched tumor and normal tissues of 13 colorectal carcinomas (Dukes' stages A-D) were analyzed using a 250K single nucleotide polymorphism array. An additional assay was performed to determine the microsatellite instability status by using the National Cancer Institute-recommended BAT-26 panel. In general, copy number gain (92.3%) was most common, followed by copy number loss (53.8%) and copy-neutral LOH (46.2%). Frequent CNAs of gains and losses were observed on chromosomes 7p, 8, 13q, 17p, 18q, and 20q, and copy-neutral LOH was observed on chromosomes 2, 6, 12, 13q, 14q, 17, 20p, 19q, and 22q. Even though genomic alterations are associated with colorectal cancer progression, our results showed that DNA CNAs and copy-neutral LOH do not reflect disease progression in at least 50% tumors. Copy-neutral LOH was observed in both early and advanced tumors, which favors the involvement of these genomic alterations in the early stages of tumor development.
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Affiliation(s)
- Y Y Yam
- Human Genome Centre, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, Kelantan, Malaysia
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12
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Therkildsen C, Jönsson G, Dominguez-Valentin M, Nissen A, Rambech E, Halvarsson B, Bernstein I, Borg K, Nilbert M. Gain of chromosomal region 20q and loss of 18 discriminates between Lynch syndrome and familial colorectal cancer. Eur J Cancer 2012; 49:1226-35. [PMID: 23245329 DOI: 10.1016/j.ejca.2012.11.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2011] [Revised: 06/07/2012] [Accepted: 11/09/2012] [Indexed: 12/24/2022]
Abstract
Lynch syndrome and familial colorectal cancer type X, FCCTX, represent the two predominant colorectal cancer syndromes. Whereas Lynch syndrome is clinically and genetically well defined, the genetic cause of FCCTX is unknown and genomic differences between Lynch syndrome and FCCTX tumours are largely unknown. We applied array-based comparative genomic hybridisation to 23 colorectal cancers from FCCTX with comparison to 23 Lynch syndrome tumours and to 45 sporadic colorectal cancers. FCCTX tumours showed genomic complexity with frequent gains on chromosomes 20q, 19 and 17 and losses of 18, 8p and 15. Gain of genetic material in two separate regions encompassing, 20q12-13.12 and 20q13.2-13.32, was identified in 65% of the FCCTX tumours. Gain of material on chromosome 20q and loss on chromosome 18 significantly discriminated colorectal cancers associated with FCCTX from Lynch syndrome, which likely signifies different preferred tumourigenic pathways.
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Affiliation(s)
- Christina Therkildsen
- The Danish HNPCC Register, Clinical Research Centre and Department of Gastroenterology, Copenhagen University Hospital, Hvidovre, Denmark.
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13
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van Wezel T, Middeldorp A, Wijnen JT, Morreau H. A review of the genetic background and tumour profiling in familial colorectal cancer. Mutagenesis 2012; 27:239-45. [PMID: 22294773 DOI: 10.1093/mutage/ger071] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Inherited predisposition plays a role in 10-30% of colorectal cancer (CRC) cases. Of the large families with a clearly positive family history of CRC, ∼40% is not affected by known CRC syndromes. The existence of families with unexplained forms of inherited CRC--familial CRC--suggests the presence of still unknown high- or moderate-risk CRC predisposing factors. While the genomic profiles of sporadic CRCs have been studied extensively, few studies have analysed the tumour profiles of hereditary or familial CRC. Here, we review recent advances in genomic tumour profiling in familial CRC in comparison with sporadic CRC. In addition, we discuss the role of known CRC risk factors in familial CRC.
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Affiliation(s)
- Tom van Wezel
- Department of Pathology, LUMC, Albinusdreef 2, 2333 ZA Leiden, The Netherlands.
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14
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de Miranda NFCC, Hes FJ, van Wezel T, Morreau H. Role of the microenvironment in the tumourigenesis of microsatellite unstable and MUTYH-associated polyposis colorectal cancers. Mutagenesis 2012; 27:247-53. [DOI: 10.1093/mutage/ger077] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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15
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Middeldorp A, van Eijk R, Oosting J, Forte GI, van Puijenbroek M, van Nieuwenhuizen M, Corver WE, Ruano D, Caldes T, Wijnen J, Morreau H, van Wezel T. Increased frequency of 20q gain and copy-neutral loss of heterozygosity in mismatch repair proficient familial colorectal carcinomas. Int J Cancer 2011; 130:837-46. [PMID: 21445971 DOI: 10.1002/ijc.26093] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2010] [Accepted: 02/14/2011] [Indexed: 12/28/2022]
Abstract
Many hereditary nonpolyposis colorectal cancers (CRCs) cannot be explained by Lynch syndrome. Other high penetrance genetic risk factors are likely to play a role in these mismatch repair (MMR)-proficient CRC families. Because genomic profiles of CRC tend to vary with CRC susceptibility syndromes, our aim is to analyze the genomic profile of MMR-proficient familial CRC to obtain insight into the biological basis of MMR-proficient familial CRC. We studied 30 MMR-proficient familial colorectal carcinomas, from 15 families, for genomic aberrations, including gains, physical losses, and copy-neutral loss of heterozygosity LOH (cnLOH) using SNP array comparative genomic hybridization. In addition, we performed somatic mutation analysis for KRAS, BRAF, PIK3CA and GNAS. The frequency of 20q gain (77%) is remarkably increased when compared with sporadic CRC, suggesting that 20q gain is involved in tumor progression of familial CRC. There is also a significant increase in the frequency of cnLOH and, as a consequence, a reduced frequency of physical loss compared with sporadic CRC. The most frequent aberrations observed included gains of 7p, 7q, 8q, 13q, 20p and 20q as well as physical losses of 17p, 18p and 18q. Most of these changes are also observed in sporadic CRC. Mutations in KRAS were identified in 37% of the MMR-proficient CRCs, and mutations in BRAF were identified in 16%. No mutations were identified in PIK3CA or chromosome 20 candidate gene GNAS. We show that the patterns of chromosomal instability of MMR-proficient familial CRC are clearly distinct from those from sporadic CRC. Both the increased gain on chromosome 20 and the increased levels of cnLOH suggest the presence of yet undiscovered germline defects that can, in part, underlie the cancer risk in these families.
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Affiliation(s)
- A Middeldorp
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
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16
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Melcher R, Hartmann E, Zopf W, Herterich S, Wilke P, Müller L, Rosler E, Kudlich T, Al-Taie O, Rosenwald A, Katzenberger T, Scholtka B, Seibold S, Rogoll D, Scheppach W, Scheurlen M, Lührs H. LOH and copy neutral LOH (cnLOH) act as alternative mechanism in sporadic colorectal cancers with chromosomal and microsatellite instability. Carcinogenesis 2011; 32:636-42. [PMID: 21297112 DOI: 10.1093/carcin/bgr011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND AND AIMS Tumor suppressor genes are often located in frequently deleted chromosomal regions of colorectal cancers (CRCs). In contrast to microsatellite stable (MSS) tumors, only few loss of heterozygosity (LOH) studies were performed in microsatellite instable (MSI) tumors, because MSI carcinomas are generally considered to be chromosomally stable and classical LOH studies are not feasible due to MSI. The single nucleotide polymorphism (SNP) array technique enables LOH studies also in MSI CRC. The aim of our study was to analyse tissue from MSI and MSS CRC for the existence of (frequently) deleted chromosomal regions and tumor suppressor genes located therein. METHODS AND RESULTS We analyzed tissues from 32 sporadic CRCs and their corresponding normal mucosa (16 MSS and 16 MSI tumors) by means of 50K SNP array analysis. MSS tumors displayed chromosomal instability that resulted in multiple deleted (LOH) and amplified regions and led to the identification of MTUS1 (8p22) as a candidate tumor suppressor gene in this region. Although the MSI tumors were chromosomally stable, we found several copy neutral LOHs (cnLOH) in the MSI tumors; these appear to be instrumental in the inactivation of the tumor suppressor gene hMLH1 and a gene located in chromosomal region 6pter-p22. DISCUSSION Our results suggest that in addition to classical LOH, cnLOH is an important mutational event in relation to the carcinogenesis of MSS and MSI tumors, causing the inactivation of a tumor suppressor gene without copy number alteration of the respective region; this is crucial for the development of MSI tumors and for some chromosomal regions in MSS tumors.
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Affiliation(s)
- Ralph Melcher
- Department of Medicine II, Division of Gastroenterology, University of Würzburg, Oberdürrbacher Strasse 6, 97080 Würzburg, Germany.
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17
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Hu N, Clifford RJ, Yang HH, Wang C, Goldstein AM, Ding T, Taylor PR, Lee MP. Genome wide analysis of DNA copy number neutral loss of heterozygosity (CNNLOH) and its relation to gene expression in esophageal squamous cell carcinoma. BMC Genomics 2010; 11:576. [PMID: 20955586 PMCID: PMC3091724 DOI: 10.1186/1471-2164-11-576] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2010] [Accepted: 10/18/2010] [Indexed: 12/14/2022] Open
Abstract
Background Genomic instability plays an important role in human cancers. We previously characterized genomic instability in esophageal squamous cell carcinomas (ESCC) in terms of loss of heterozygosity (LOH) and copy number (CN) changes in tumors using the Affymetrix GeneChip Human Mapping 500K array in 30 cases from a high-risk region of China. In the current study we focused on copy number neutral (CN = 2) LOH (CNNLOH) and its relation to gene expression in ESCC. Results Overall we found that 70% of all LOH observed was CNNLOH. Ninety percent of ESCCs showed CNNLOH (median frequency in cases = 60%) and this was the most common type of LOH in two-thirds of cases. CNNLOH occurred on all 39 autosomal chromosome arms, with highest frequencies on 19p (100%), 5p (96%), 2p (95%), and 20q (95%). In contrast, LOH with CN loss represented 19% of all LOH, occurred in just half of ESCCs (median frequency in cases = 0%), and was most frequent on 3p (56%), 5q (47%), and 21q (41%). LOH with CN gain was 11% of all LOH, occurred in 93% of ESCCs (median frequency in cases = 13%), and was most common on 20p (82%), 8q (74%), and 3q (42%). To examine the effect of genomic instability on gene expression, we evaluated RNA profiles from 17 pairs of matched normal and tumor samples (a subset of the 30 ESCCs) using Affymetrix U133A 2.0 arrays. In CN neutral regions, expression of 168 genes (containing 1976 SNPs) differed significantly in tumors with LOH versus tumors without LOH, including 101 genes that were up-regulated and 67 that were down-regulated. Conclusion Our results indicate that CNNLOH has a profound impact on gene expression in ESCC, which in turn may affect tumor development.
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Affiliation(s)
- Nan Hu
- Genetic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, DHHS, Bethesda, Maryland, USA
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van Riel E, Ausems MG, Hogervorst FB, Kluijt I, van Gijn ME, van Echtelt J, Scheidel-Jacobse K, Hennekam EF, Stulp RP, Vos YJ, Offerhaus GJA, Menko FH, Gille JJ. A novel pathogenic MLH1 missense mutation, c.112A > C, p.Asn38His, in six families with Lynch syndrome. Hered Cancer Clin Pract 2010; 8:7. [PMID: 20704743 PMCID: PMC2927519 DOI: 10.1186/1897-4287-8-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Accepted: 08/12/2010] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND An unclassified variant (UV) in exon 1 of the MLH1 gene, c.112A > C, p.Asn38His, was found in six families who meet diagnostic criteria for Lynch syndrome. The pathogenicity of this variant was unknown. We aim to elucidate the pathogenicity of this MLH1 variant in order to counsel these families adequately and to enable predictive testing in healthy at-risk relatives. METHODS We studied clinical data, microsatellite instability and immunohistochemical staining of MMR proteins, and performed genealogy, haplotype analysis and DNA testing of control samples. RESULTS The UV showed co-segregation with the disease in all families. All investigated tumors showed a microsatellite instable pattern. Immunohistochemical data were variable among tested tumors. Three families had a common ancestor and all families originated from the same geographical area in The Netherlands. Haplotype analysis showed a common haplotype in all six families. CONCLUSIONS We conclude that the MLH1 variant is a pathogenic mutation and genealogy and haplotype analysis results strongly suggest that it is a Dutch founder mutation. Our findings imply that predictive testing can be offered to healthy family members. The immunohistochemical data of MMR protein expression show that interpreting these results in case of a missense mutation should be done with caution.
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Affiliation(s)
- Els van Riel
- Department of Medical Genetics, University Medical Centre Utrecht, Lundlaan 6, Utrecht, The Netherlands.
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Middeldorp A, Jagmohan-Changur SC, van der Klift HM, van Puijenbroek M, Houwing-Duistermaat JJ, Webb E, Houlston R, Tops C, Vasen HFA, Devilee P, Morreau H, van Wezel T, Wijnen J. Comprehensive genetic analysis of seven large families with mismatch repair proficient colorectal cancer. Genes Chromosomes Cancer 2010; 49:539-48. [PMID: 20222047 DOI: 10.1002/gcc.20763] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Approximately 40% of colorectal cancer (CRC) families with a diagnosis of hereditary nonpolyposis CRC on the basis of clinical criteria are not a consequence of mismatch repair (MMR) deficiency. Such families provide supporting evidence for the existence of a hitherto unidentified highly penetrant gene mutation. To gain further understanding of MMR-competent familial colorectal cancer (FCC), we studied seven large families with an unexplained predisposition for CRC to identify genetic regions that could harbor CRC risk factors. First, we conducted a genome-wide linkage scan using 10K single-nucleotide polymorphism (SNP) arrays to search for disease loci. Second, we studied the genomic profiles of the tumors of affected family members to identify commonly altered genomic regions likely to harbor tumor suppressor genes. Finally, we studied the possible role of recently identified low-risk variants in the familial aggregation of CRC in these families. Linkage analysis did not reveal clear regions of linkage to CRC. However, our results provide support linkage to 3q, a region that has previously been linked to CRC susceptibility. Tumor profiling did not reveal any genomic regions commonly targeted in the tumors studied here. Overall, the genomic profiles of the tumors show some resemblance to sporadic CRC, but additional aberrations were also present. Furthermore, the FCC families did not appear to have an enrichment of low-risk CRC susceptibility loci. These data suggest that factors other than a highly penetrant risk factor, such as low or moderate-penetrance risk factors, may explain the increased cancer risk in a subset of familial CRCs.
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Affiliation(s)
- Anneke Middeldorp
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
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20
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van Roon EHJ, van Puijenbroek M, Middeldorp A, van Eijk R, de Meijer EJ, Erasmus D, Wouters KAD, van Engeland M, Oosting J, Hes FJ, Tops CMJ, van Wezel T, Boer JM, Morreau H. Early onset MSI-H colon cancer with MLH1 promoter methylation, is there a genetic predisposition? BMC Cancer 2010; 10:180. [PMID: 20444249 PMCID: PMC2880297 DOI: 10.1186/1471-2407-10-180] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 05/05/2010] [Indexed: 12/12/2022] Open
Abstract
Background To investigate the etiology of MLH1 promoter methylation in mismatch repair (MMR) mutation-negative early onset MSI-H colon cancer. As this type of colon cancer is associated with high ages, young patients bearing this type of malignancy are rare and could provide additional insight into the etiology of sporadic MSI-H colon cancer. Methods We studied a set of 46 MSI-H colon tumors cases with MLH1 promoter methylation which was enriched for patients with an age of onset below 50 years (n = 13). Tumors were tested for CIMP marker methylation and mutations linked to methylation: BRAF, KRAS, GADD45A and the MLH1 -93G>A polymorphism. When available, normal colon and leukocyte DNA was tested for GADD45A mutations and germline MLH1 methylation. SNP array analysis was performed on a subset of tumors. Results We identified two cases (33 and 60 years) with MLH1 germline promoter methylation. BRAF mutations were less frequent in colon cancer patients below 50 years relative to patients above 50 years (p-value: 0.044). CIMP-high was infrequent and related to BRAF mutations in patients below 50 years. In comparison with published controls the G>A polymorphism was associated with our cohort. Although similar distribution of the pathogenic A allele was observed in the patients with an age of onset above and below 50 years, the significance for the association was lost for the group under 50 years. GADD45A sequencing yielded an unclassified variant. Tumors from both age groups showed infrequent copy number changes and loss-of-heterozygosity. Conclusion Somatic or germline GADD45A mutations did not explain sporadic MSI-H colon cancer. Although germline MLH1 methylation was found in two individuals, locus-specific somatic MLH1 hypermethylation explained the majority of sporadic early onset MSI-H colon cancer cases. Our data do not suggest an intrinsic tendency for CpG island hypermethylation in these early onset MSI-H tumors other than through somatic mutation of BRAF.
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Affiliation(s)
- Eddy H J van Roon
- Department of Pathology, Leiden University Medical Center, Leiden, The Netherlands
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Zavodna K, Krivulcik T, Bujalkova MG, Slamka T, Martinicky D, Ilencikova D, Bartosova Z. Partial loss of heterozygosity events at the mutated gene in tumors from MLH1/MSH2 large genomic rearrangement carriers. BMC Cancer 2009; 9:405. [PMID: 19930554 PMCID: PMC2788582 DOI: 10.1186/1471-2407-9-405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 11/20/2009] [Indexed: 11/24/2022] Open
Abstract
Background Depending on the population studied, large genomic rearrangements (LGRs) of the mismatch repair (MMR) genes constitute various proportions of the germline mutations that predispose to hereditary non-polyposis colorectal cancer (HNPCC). It has been reported that loss of heterozygosity (LOH) at the LGR region occurs through a gene conversion mechanism in tumors from MLH1/MSH2 deletion carriers; however, the converted tracts were delineated only by extragenic microsatellite markers. We sought to determine the frequency of LGRs in Slovak HNPCC patients and to study LOH in tumors from LGR carriers at the LGR region, as well as at other heterozygous markers within the gene to more precisely define conversion tracts. Methods The main MMR genes responsible for HNPCC, MLH1, MSH2, MSH6, and PMS2, were analyzed by MLPA (multiplex ligation-dependent probe amplification) in a total of 37 unrelated HNPCC-suspected patients whose MLH1/MSH2 genes gave negative results in previous sequencing experiments. An LOH study was performed on six tumors from LGR carriers by combining MLPA to assess LOH at LGR regions and sequencing to examine LOH at 28 SNP markers from the MLH1 and MSH2 genes. Results We found six rearrangements in the MSH2 gene (five deletions and dup5-6), and one aberration in the MLH1 gene (del5-6). The MSH2 deletions were of three types (del1, del1-3, del1-7). We detected LOH at the LGR region in the single MLH1 case, which was determined in a previous study to be LOH-negative in the intragenic D3S1611 marker. Three tumors displayed LOH of at least one SNP marker, including two cases that were LOH-negative at the LGR region. Conclusion LGRs accounted for 25% of germline MMR mutations identified in 28 Slovakian HNPCC families. A high frequency of LGRs among the MSH2 mutations provides a rationale for a MLPA screening of the Slovakian HNPCC families prior scanning by DNA sequencing. LOH at part of the informative loci confined to the MLH1 or MSH2 gene (heterozygous LGR region, SNP, or microsatellite) is a novel finding and can be regarded as a partial LOH. The conversion begins within the gene, and the details of conversion tracts are discussed for each case.
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Affiliation(s)
- Katarina Zavodna
- Laboratory of Cancer Genetics, Cancer Research Institute of Slovak Academy of Sciences, Vlarska 7, 833 91 Bratislava, Slovak Republic.
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Middeldorp A, van Puijenbroek M, Nielsen M, Corver WE, Jordanova ES, ter Haar N, Tops CMJ, Vasen HFA, Lips EH, van Eijk R, Hes FJ, Oosting J, Wijnen J, van Wezel T, Morreau H. High frequency of copy-neutral LOH in MUTYH-associated polyposis carcinomas. J Pathol 2008; 216:25-31. [PMID: 18506705 DOI: 10.1002/path.2375] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Genetic instability is known to drive colorectal carcinogenesis. Generally, a distinction is made between two types of genetic instability: chromosomal instability (CIN) and microsatellite instability (MIN or MSI). Most CIN tumours are aneuploid, whereas MSI tumours are considered near-diploid. However, for MUTYH-associated polyposis (MAP) the genetic instability involved in the carcinogenesis remains unclear, as near-diploid adenomas, aneuploid adenomas and near-diploid carcinomas have been reported. Remarkably, our analysis of 26 MAP carcinomas, using SNP arrays and flow sorting, showed that these tumours are often near-diploid (52%) and mainly contain chromosomal regions of copy-neutral loss of heterozygosity (LOH) (71%). This is in contrast to sporadic colon cancer, where physical loss is the main characteristic. The percentage of chromosomal gains (24%) is comparable to sporadic colorectal cancers with CIN. Furthermore, we verified our scoring of copy-neutral LOH versus physical loss in MAP carcinomas by two methods: fluorescence in situ hybridization, and LOH analysis using polymorphic markers on carcinoma fractions purified by flow sorting. The results presented in this study suggest that copy-neutral LOH is an important mechanism in the tumorigenesis of MAP.
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Affiliation(s)
- A Middeldorp
- Department of Pathology, Leiden University Medical Centre, Leiden, The Netherlands
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