1
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Vogelaar IP, Greer S, Wang F, Shin G, Lau B, Hu Y, Haraldsdottir S, Alvarez R, Hazelett D, Nguyen P, Aguirre FP, Guindi M, Hendifar A, Balcom J, Leininger A, Fairbank B, Ji H, Hitchins MP. Large Cancer Pedigree Involving Multiple Cancer Genes including Likely Digenic MSH2 and MSH6 Lynch Syndrome (LS) and an Instance of Recombinational Rescue from LS. Cancers (Basel) 2022; 15:cancers15010228. [PMID: 36612224 PMCID: PMC9818763 DOI: 10.3390/cancers15010228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/26/2022] [Accepted: 12/28/2022] [Indexed: 12/31/2022] Open
Abstract
Lynch syndrome (LS), caused by heterozygous pathogenic variants affecting one of the mismatch repair (MMR) genes (MSH2, MLH1, MSH6, PMS2), confers moderate to high risks for colorectal, endometrial, and other cancers. We describe a four-generation, 13-branched pedigree in which multiple LS branches carry the MSH2 pathogenic variant c.2006G>T (p.Gly669Val), one branch has this and an additional novel MSH6 variant c.3936_4001+8dup (intronic), and other non-LS branches carry variants within other cancer-relevant genes (NBN, MC1R, PTPRJ). Both MSH2 c.2006G>T and MSH6 c.3936_4001+8dup caused aberrant RNA splicing in carriers, including out-of-frame exon-skipping, providing functional evidence of their pathogenicity. MSH2 and MSH6 are co-located on Chr2p21, but the two variants segregated independently (mapped in trans) within the digenic branch, with carriers of either or both variants. Thus, MSH2 c.2006G>T and MSH6 c.3936_4001+8dup independently confer LS with differing cancer risks among family members in the same branch. Carriers of both variants have near 100% risk of transmitting either one to offspring. Nevertheless, a female carrier of both variants did not transmit either to one son, due to a germline recombination within the intervening region. Genetic diagnosis, risk stratification, and counseling for cancer and inheritance were highly individualized in this family. The finding of multiple cancer-associated variants in this pedigree illustrates a need to consider offering multicancer gene panel testing, as opposed to targeted cascade testing, as additional cancer variants may be uncovered in relatives.
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Affiliation(s)
- Ingrid P. Vogelaar
- Department of Medicine (Oncology), Stanford Cancer Institute, Stanford University, Stanford, CA 94305, USA
| | - Stephanie Greer
- Department of Medicine (Oncology), Stanford Cancer Institute, Stanford University, Stanford, CA 94305, USA
| | - Fan Wang
- Department of Medicine (Oncology), Stanford Cancer Institute, Stanford University, Stanford, CA 94305, USA
- School of Public Health (Epidemiology), Harbin Medical University, Harbin 150088, China
| | - GiWon Shin
- Department of Medicine (Oncology), Stanford Cancer Institute, Stanford University, Stanford, CA 94305, USA
| | - Billy Lau
- Department of Medicine (Oncology), Stanford Cancer Institute, Stanford University, Stanford, CA 94305, USA
| | - Yajing Hu
- Department of Medicine (Oncology), Stanford Cancer Institute, Stanford University, Stanford, CA 94305, USA
| | - Sigurdis Haraldsdottir
- Department of Medicine (Oncology), Stanford Cancer Institute, Stanford University, Stanford, CA 94305, USA
| | - Rocio Alvarez
- Bioinformatics and Functional Genomics Center, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Dennis Hazelett
- Bioinformatics and Functional Genomics Center, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Peter Nguyen
- Bioinformatics and Functional Genomics Center, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Francesca P. Aguirre
- Bioinformatics and Functional Genomics Center, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Maha Guindi
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Andrew Hendifar
- Samuel Oschin Cancer Center, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Los Angeles, CA 90048, USA
| | - Jessica Balcom
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55902, USA
| | | | - Beth Fairbank
- Lynch Syndrome Australia, The Summit, QLD 4377, Australia
| | - Hanlee Ji
- Department of Medicine (Oncology), Stanford Cancer Institute, Stanford University, Stanford, CA 94305, USA
- Stanford Genome Technology Center West, 1050 Arastradero, Palo Alto, CA 94304, USA
| | - Megan P. Hitchins
- Department of Medicine (Oncology), Stanford Cancer Institute, Stanford University, Stanford, CA 94305, USA
- Bioinformatics and Functional Genomics Center, Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Lowy Cancer Research Centre, University of New South Wales, Sydney, NSW 2052, Australia
- Correspondence: ; Tel.: +310-423-8785
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de Paula AE, Galvão HDCR, Bonatelli M, Sabato C, Fernandes GC, Berardinelli GN, Andrade CEM, Neto MC, Romagnolo LGC, Campacci N, Scapulatempo-Neto C, Reis RM, Palmero EI. Clinicopathological and molecular characterization of Brazilian families at risk for Lynch syndrome. Cancer Genet 2021; 254-255:82-91. [PMID: 33647816 DOI: 10.1016/j.cancergen.2021.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/14/2020] [Accepted: 02/08/2021] [Indexed: 11/25/2022]
Abstract
Lynch syndrome (LS), is the most common hereditary colorectal cancer syndrome. However, it is poorly characterized in Brazil. Therefore, we aimed to determine the spectrum of pathogenic variants in Mismatch Repair (MMR) genes and investigate the MLH1 promotor methylation role as a second hit in LS tumors. Tumor screening through microsatellite instability and immunohistochemistry for MMR proteins was performed in 323 cases who met clinical criteria. BRAF-V600E and MLH1 promoter methylation were analyzed for all MLH1-deficient tumors. Patients with MMR deficient tumor proceeded to germline genetic testing. MMR deficient tumors were detected in 41% of patients recruited. About half of patients carried a pathogenic germline variant. Two recurrent variants in MLH1 and three novel pathogenic variants were identified. Furthermore, pathogenic germline variants with concomitant somatic MLH1 hypermethylation were found in 6% of cases. Predictive genetic testing was offered to 387 relatives. Overall, 127 tumors were diagnosed in 100 LS patients, from 62 unrelated families. Our molecular data provide new information about the spectrum of MMR mutations, which contributes to a better characterization of LS in Brazil. Furthermore, we call attention to the possibility of failure in the diagnosis of germline MLH1 mutation carriers when somatic MLH1 hypermethylation is used to rule out LS.
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Affiliation(s)
| | | | - Murilo Bonatelli
- Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, São Paulo, Brazil
| | - Cristina Sabato
- Molecular Diagnosis Laboratory, Barretos Cancer Hospital, Barretos, São Paulo, Brazil
| | | | | | | | | | | | - Natalia Campacci
- Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, São Paulo, Brazil
| | | | - Rui Manuel Reis
- Molecular Diagnosis Laboratory, Barretos Cancer Hospital, Barretos, São Paulo, Brazil; Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, São Paulo, Brazil; Life and Health Sciences Research Institute (ICVS), Health Sciences School, University of Minho, Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Edenir Inêz Palmero
- Molecular Diagnosis Laboratory, Barretos Cancer Hospital, Barretos, São Paulo, Brazil; Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, São Paulo, Brazil; Pele Pequeno Principe Research Institute, Curitiba, Brazil; Faculdades Pequeno Principe, Curitiba, Brazil.
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3
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Singh AK, Talseth-Palmer B, McPhillips M, Lavik LAS, Xavier A, Drabløs F, Sjursen W. Targeted sequencing of genes associated with the mismatch repair pathway in patients with endometrial cancer. PLoS One 2020; 15:e0235613. [PMID: 32634176 PMCID: PMC7340288 DOI: 10.1371/journal.pone.0235613] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 06/19/2020] [Indexed: 01/28/2023] Open
Abstract
Germline variants inactivating the mismatch repair (MMR) genes MLH1, MSH2, MSH6 and PMS2 cause Lynch syndrome that implies an increased cancer risk, where colon and endometrial cancer are the most frequent. Identification of these pathogenic variants is important to identify endometrial cancer patients with inherited increased risk of new cancers, in order to offer them lifesaving surveillance. However, several other genes are also part of the MMR pathway. It is therefore relevant to search for variants in additional genes that may be associated with cancer risk by including all known genes involved in the MMR pathway. Next-generation sequencing was used to screen 22 genes involved in the MMR pathway in constitutional DNA extracted from full blood from 199 unselected endometrial cancer patients. Bioinformatic pipelines were developed for identification and functional annotation of variants, using several different software tools and custom programs. This facilitated identification of 22 exonic, 4 UTR and 9 intronic variants that could be classified according to pathogenicity. This study has identified several germline variants in genes of the MMR pathway that potentially may be associated with an increased risk for cancer, in particular endometrial cancer, and therefore are relevant for further investigation. We have also developed bioinformatics strategies to analyse targeted sequencing data, including low quality data and genomic regions outside of the protein coding exons of the relevant genes.
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Affiliation(s)
- Ashish Kumar Singh
- Department of Medical Genetics, St. Olavs Hospital, Trondheim, Norway
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, NTNU—Norwegian University of Science and Technology, Trondheim, Norway
| | - Bente Talseth-Palmer
- Department of Medical Genetics, St. Olavs Hospital, Trondheim, Norway
- School of Biomedical Science and Pharmacy, Faculty of Health and Medicine, University of Newcastle and Hunter Medical Research Institute, Newcastle, Australia
- Department of Research and Development, Møre og Romsdal Hospital Trust, Molde, Norway
| | - Mary McPhillips
- NSW Health Pathology, Molecular Medicine, John Hunter Hospital, Newcastle, NSW, Australia
| | | | - Alexandre Xavier
- School of Biomedical Science and Pharmacy, Faculty of Health and Medicine, University of Newcastle and Hunter Medical Research Institute, Newcastle, Australia
| | - Finn Drabløs
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, NTNU—Norwegian University of Science and Technology, Trondheim, Norway
| | - Wenche Sjursen
- Department of Medical Genetics, St. Olavs Hospital, Trondheim, Norway
- Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, NTNU—Norwegian University of Science and Technology, Trondheim, Norway
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Schneider NB, Pastor T, de Paula AE, Achatz MI, dos Santos ÂR, Vianna FSL, Rosset C, Pinheiro M, Ashton‐Prolla P, Moreira MÂM, Palmero EI. Germline MLH1, MSH2 and MSH6 variants in Brazilian patients with colorectal cancer and clinical features suggestive of Lynch Syndrome. Cancer Med 2018; 7:2078-2088. [PMID: 29575718 PMCID: PMC5943474 DOI: 10.1002/cam4.1316] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 11/20/2017] [Accepted: 11/27/2017] [Indexed: 12/13/2022] Open
Abstract
Lynch syndrome (LS) is the most common hereditary colorectal cancer syndrome, caused by germline mutations in one of the major genes involved in mismatch repair (MMR): MLH1,MSH2,MSH6 and more rarely, PMS2. Recently, germline deletions in EPCAM have been also associated to the syndrome. Most of the pathogenic MMR mutations found in LS families occur in MLH1 or MSH2. Gene variants include missense, nonsense, frameshift mutations, large genomic rearrangements and splice‐site variants and most of the studies reporting the molecular characterization of LS families have been conducted outside South America. In this study, we analyzed 60 unrelated probands diagnosed with colorectal cancer and LS criteria. Testing for germline mutations and/or rearrangements in the most commonly affected MMR genes (MLH1, MSH2, EPCAM and MSH6) was done by Sanger sequencing and MLPA. Pathogenic or likely pathogenic variants were identified in MLH1 or MSH2 in 21 probands (35.0%). Of these, approximately one‐third were gene rearrangements. In addition, nine variants of uncertain significance (VUS) were identified in 10 (16.6%) of the sixty probands analyzed. Other four novel variants were identified, only in MLH1. Our results suggest that MSH6 pathogenic variants are not common among Brazilian LS probands diagnosed with CRC and that MMR gene rearrangements account for a significant proportion of the germline variants in this population underscoring the need to include rearrangement analysis in the molecular testing of Brazilian individuals with suspected Lynch syndrome.
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Affiliation(s)
- Nayê Balzan Schneider
- Laboratório de Medicina GenômicaCentro de Pesquisa ExperimentalHospital de Clínicas de Porto Alegre (HCPA) and Programa de Pós Graduação em Genética e Biologia MolecularUniversidade Federal do Rio Grande do Sul (UFRGS)Porto AlegreBrazil
| | - Tatiane Pastor
- Genetics ProgramInstituto Nacional de CâncerRio de JaneiroBrazil
| | | | - Maria Isabel Achatz
- AC Camargo Cancer CenterSão PauloBrazil
- Clinical Genetics BranchDivision of Cancer Epidemiology and GeneticsDepartment of Health and Human ServicesNational Cancer InstituteNational Institutes of HealthBethesdaMaryland
| | - Ândrea Ribeiro dos Santos
- Núcleo de Pesquisas Oncológicas and Laboratório de Genética Humana e MédicaUniversidade Federal do Pará Universidade Federal do Pará (UFPA)BelémBrazil
| | - Fernanda Sales Luiz Vianna
- Laboratório de Pesquisa em Bioética e Ética na Ciência‐ LAPEBEC ‐ Centro de Pesquisa ExperimentalHospital de Clínicas de Porto AlegrePorto AlegreBrazil
| | - Clévia Rosset
- Laboratório de Medicina GenômicaCentro de Pesquisa ExperimentalHospital de Clínicas de Porto Alegre (HCPA) and Programa de Pós Graduação em Genética e Biologia MolecularUniversidade Federal do Rio Grande do Sul (UFRGS)Porto AlegreBrazil
| | - Manuela Pinheiro
- Serviço de GenéticaInstituto Português de Oncologia do Porto (IPO Porto)PortoPortugal
| | - Patricia Ashton‐Prolla
- Laboratório de Medicina GenômicaCentro de Pesquisa ExperimentalHospital de Clínicas de Porto Alegre (HCPA) and Programa de Pós Graduação em Genética e Biologia MolecularUniversidade Federal do Rio Grande do Sul (UFRGS)Porto AlegreBrazil
| | | | - Edenir Inêz Palmero
- Molecular Oncology Research CenterBarretos Cancer HospitalBarretosBrazil
- Barretos School of Health SciencesDr. Paulo Prata – FACISBBarretosBrazil
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Houlleberghs H, Goverde A, Lusseveld J, Dekker M, Bruno MJ, Menko FH, Mensenkamp AR, Spaander MCW, Wagner A, Hofstra RMW, te Riele H. Suspected Lynch syndrome associated MSH6 variants: A functional assay to determine their pathogenicity. PLoS Genet 2017; 13:e1006765. [PMID: 28531214 PMCID: PMC5460888 DOI: 10.1371/journal.pgen.1006765] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 06/06/2017] [Accepted: 04/18/2017] [Indexed: 12/14/2022] Open
Abstract
Lynch syndrome (LS) is a hereditary cancer predisposition caused by inactivating mutations in DNA mismatch repair (MMR) genes. Mutations in the MSH6 DNA MMR gene account for approximately 18% of LS cases. Many LS-associated sequence variants are nonsense and frameshift mutations that clearly abrogate MMR activity. However, missense mutations whose functional implications are unclear are also frequently seen in suspected-LS patients. To conclusively diagnose LS and enroll patients in appropriate surveillance programs to reduce morbidity as well as mortality, the functional consequences of these variants of uncertain clinical significance (VUS) must be defined. We present an oligonucleotide-directed mutagenesis screen for the identification of pathogenic MSH6 VUS. In the screen, the MSH6 variant of interest is introduced into mouse embryonic stem cells by site-directed mutagenesis. Subsequent selection for MMR-deficient cells using the DNA damaging agent 6-thioguanine (6TG) allows the identification of MMR abrogating VUS because solely MMR-deficient cells survive 6TG exposure. We demonstrate the efficacy of the genetic screen, investigate the phenotype of 26 MSH6 VUS and compare our screening results to clinical data from suspected-LS patients carrying these variant alleles. The colorectal and endometrial cancer predisposition Lynch syndrome (LS) is caused by an inherited heterozygous defect in one of four DNA mismatch repair (MMR) genes. Deleterious mutations (e.g., protein-deleting or -truncating) in DNA MMR genes unambiguously allow for the clinical diagnosis LS and hence enable appropriate surveillance measures to be taken to reduce cancer risk and ensure early detection of tumors. However, currently about one-third of detected MMR gene variants are subtle with less clear functional consequences: missense mutations affecting a single amino acid may be innocuous, hence not causing LS, or partially or fully destroy protein function. As long as uncertainty exists about their pathogenicity, such mutations are labeled ‘variants of uncertain (clinical) significance’ (VUS). VUS hamper genetic counseling and therefore the need for functional testing of VUS is widely recognized. To functionally annotate MMR gene VUS, we have developed a high content cellular assay in which the VUS is introduced in a cell culture by oligonucleotide-directed gene modification. Should the VUS be deleterious for MMR, the modified cells survive exposure to the guanine analog 6-thioguanine (6TG) and 6TG-resistant colonies appear. Should the mutation not affect MMR, no colonies appear. Here we present the adaptation and application of this protocol to the functional annotation of variants of the MMR gene MSH6. Implementation of our assay in clinical genetics laboratories will provide clinicians with information for proper counseling of mutation carriers and treatment of their of tumors.
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Affiliation(s)
- Hellen Houlleberghs
- Division of Biological Stress Response, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Anne Goverde
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jarnick Lusseveld
- Division of Biological Stress Response, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Marleen Dekker
- Division of Biological Stress Response, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Marco J. Bruno
- Department of Gastroenterology and Hepatology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Fred H. Menko
- Family Cancer Clinic, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Arjen R. Mensenkamp
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Manon C. W. Spaander
- Department of Gastroenterology and Hepatology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Anja Wagner
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Robert M. W. Hofstra
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Hein te Riele
- Division of Biological Stress Response, The Netherlands Cancer Institute, Amsterdam, The Netherlands
- * E-mail:
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6
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Abstract
Lynch syndrome, an autosomal dominant inherited disorder, is caused by inactivating mutations involving DNA mismatch repair (MMR) genes. This leads to profound genetic instability, including microsatellite instability (MSI) and increased risk for cancer development, particularly colon and endometrial malignancies. Clinical testing of tumor tissues for the presence of MMR gene deficiency is standard practice in clinical oncology, with immunohistochemistry and PCR-based microsatellite instability analysis used as screening tests to identify potential Lynch syndrome families. The ultimate diagnosis of Lynch syndrome requires documentation of mutation within one of the four MMR genes (MLH1, PMS2, MSH2 and MSH6) or EPCAM, currently achieved by comprehensive sequencing analysis of germline DNA. In this review, the genetic basis of Lynch syndrome, methodologies of MMR deficiency testing, and current diagnostic algorithms in the clinical management of Lynch syndrome, are discussed.
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Affiliation(s)
- Natalia Buza
- a Department of Pathology, School of Medicine , Yale University , New Haven , CT , USA
| | - James Ziai
- b Genentech Inc ., San Francisco , CA , USA
| | - Pei Hui
- a Department of Pathology, School of Medicine , Yale University , New Haven , CT , USA
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7
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Hegde M, Ferber M, Mao R, Samowitz W, Ganguly A. ACMG technical standards and guidelines for genetic testing for inherited colorectal cancer (Lynch syndrome, familial adenomatous polyposis, and MYH-associated polyposis). Genet Med 2013; 16:101-16. [PMID: 24310308 DOI: 10.1038/gim.2013.166] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 09/17/2013] [Indexed: 12/28/2022] Open
Abstract
Lynch syndrome, familial adenomatous polyposis, and Mut Y homolog (MYH)-associated polyposis are three major known types of inherited colorectal cancer, which accounts for up to 5% of all colon cancer cases. Lynch syndrome is most frequently caused by mutations in the mismatch repair genes MLH1, MSH2, MSH6, and PMS2 and is inherited in an autosomal dominant manner. Familial adenomatous polyposis is manifested as colonic polyposis caused by mutations in the APC gene and is also inherited in an autosomal dominant manner. Finally, MYH-associated polyposis is caused by mutations in the MUTYH gene and is inherited in an autosomal recessive manner but may or may not be associated with polyps. There are variants of both familial adenomatous polyposis (Gardner syndrome--with extracolonic features--and Turcot syndrome, which features medulloblastoma) and Lynch syndrome (Muir-Torre syndrome features sebaceous skin carcinomas, and Turcot syndrome features glioblastomas). Although a clinical diagnosis of familial adenomatous polyposis can be made using colonoscopy, genetic testing is needed to inform at-risk relatives. Because of the overlapping phenotypes between attenuated familial adenomatous polyposis, MYH-associated polyposis, and Lynch syndrome, genetic testing is needed to distinguish among these conditions. This distinction is important, especially for women with Lynch syndrome, who are at increased risk for gynecological cancers. Clinical testing for these genes has progressed rapidly in the past few years with advances in technologies and the lower cost of reagents, especially for sequencing. To assist clinical laboratories in developing and validating testing for this group of inherited colorectal cancers, the American College of Medical Genetics and Genomics has developed the following technical standards and guidelines. An algorithm for testing is also proposed.
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Affiliation(s)
- Madhuri Hegde
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | | | - Rong Mao
- Mayo Clinic, Salt Lake City, Utah, USA
| | | | - Arupa Ganguly
- University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Pei C, Chen H, Jia X, Yan L, Zou Y, Jiang C, Jin H, Kang C, Jiang T, Ren H. A high frequency of MSH6 G268A polymorphism and survival association in glioblastoma. Int J Neurosci 2012; 123:114-20. [PMID: 23057844 DOI: 10.3109/00207454.2012.738735] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
MSH6 (mutS homolog 6), one of the five key mismatch repair (MMR) genes, was found to play an important role in conferring resistance to alkylating agents-temozolomide (TMZ) in malignant glioma. This study aims to investigate whether genetic variations in MSH6 gene are associated with the survival outcomes in patients with malignant glioma. Each exon of the MSH6 gene was sequenced, and single nucleotide polymorphism (SNP) analysis was performed using 74 tumor tissues from glioblastoma multiforme (GBM) patients. Among these patients, 54 patients received radiotherapy plus TMZ treatment; 20 patients had radiotherapy only. The promoter methylation of O6-methylguanine methyltransferase (MGMT) was measured by methylation-specific polymerase chain reaction. Literature mining and related data collection were done with NCBI and PubMed databases. Of the 74 GBM patients, 50% (n = 37) harbored MSH6 G268A polymorphism, and no significant rates of other SNP or gene mutation across MSH6 exons were detected. The median overall survival (OS) was 15.6 months for who harbored the SNP and 12.6 months for SNP-negative patients (log-rank test: p = .324). The median OS for the MGMT promoter methylation group (n = 25) and nonmethylation group (n = 29) of the 54 GBM patients treated with TMZ was 21.3 and 8.9 months, respectively, (p = .002). In conclusion, we identified a high frequency of MSH6 G268A polymorphism in MSH6 gene, which did not have a notable influence on survival for the malignant glioma patients with/without TMZ treatment.
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Affiliation(s)
- Chunying Pei
- Department of Immunology, Harbin Medical University, Harbin, China
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Medeiros F, Lindor NM, Couch FJ, Highsmith WE. The germline MLH1 K618A variant and susceptibility to Lynch syndrome-associated tumors. J Mol Diagn 2012; 14:264-73. [PMID: 22426235 DOI: 10.1016/j.jmoldx.2012.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 12/22/2011] [Accepted: 01/10/2012] [Indexed: 12/31/2022] Open
Abstract
Missense variants discovered during sequencing of cancer susceptibility genes can be problematic for clinical interpretation. MLH1 K618A, which results from a 2-bp alteration (AAG→GCG) leading to a substitution of lysine to alanine in codon 618, has variously been interpreted as a pathogenic mutation, a variant of unknown significance, and a benign polymorphism. We evaluated the role of MLH1 K618A in predisposition to cancer by genotyping 1512 control subjects to assess its frequency in the general population. We also reviewed the literature concerning MLH1 K618A in families with colorectal cancer. The measured allele frequency of the K618A variant was 0.40%, which is remarkably close to the 0.44% summarized from 2491 control subjects in the literature. K618A was over-represented in families with suspected Lynch syndrome. In 1366 families, the allele frequency was 0.88% (OR = 2.1, 95% CI = 1.3 to 3.5; P = 0.006). In studies of sporadic cancers of the type associated with Lynch syndrome, K618A was over-represented in 1742 cases (allele frequency of 0.83) (OR = 2.0, 95% CI = 1.2 to 3.2; P = 0.008). We conclude that MLH1 K618A is not a fully penetrant Lynch syndrome mutation, although it is not without effect, appearing to increase the risk of Lynch syndrome-associated tumors approximately twofold. Our systematic assessment approach may be useful for variants in other genes.
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Affiliation(s)
- Fabiola Medeiros
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
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Viana-Pereira M, Lee A, Popov S, Bax DA, Al-Sarraj S, Bridges LR, Stávale JN, Hargrave D, Jones C, Reis RM. Microsatellite instability in pediatric high grade glioma is associated with genomic profile and differential target gene inactivation. PLoS One 2011; 6:e20588. [PMID: 21637783 PMCID: PMC3102740 DOI: 10.1371/journal.pone.0020588] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 05/06/2011] [Indexed: 12/14/2022] Open
Abstract
High grade gliomas (HGG) are one of the leading causes of cancer-related deaths in children, and there is increasing evidence that pediatric HGG may harbor distinct molecular characteristics compared to adult tumors. We have sought to clarify the role of microsatellite instability (MSI) in pediatric versus adult HGG. MSI status was determined in 144 patients (71 pediatric and 73 adults) using a well established panel of five quasimonomorphic mononucleotide repeat markers. Expression of MLH1, MSH2, MSH6 and PMS2 was determined by immunohistochemistry, MLH1 was assessed for mutations by direct sequencing and promoter methylation using MS-PCR. DNA copy number profiles were derived using array CGH, and mutations in eighteen MSI target genes studied by multiplex PCR and genotyping. MSI was found in 14/71 (19.7%) pediatric cases, significantly more than observed in adults (5/73, 6.8%; p = 0.02, Chi-square test). MLH1 expression was downregulated in 10/13 cases, however no mutations or promoter methylation were found. MSH6 was absent in one pediatric MSI-High tumor, consistent with an inherited mismatch repair deficiency associated with germline MSH6 mutation. MSI was classed as Type A, and associated with a remarkably stable genomic profile. Of the eighteen classic MSI target genes, we identified mutations only in MSH6 and DNAPKcs and described a polymorphism in MRE11 without apparent functional consequences in DNA double strand break detection and repair. This study thus provides evidence for a potential novel molecular pathway in a proportion of gliomas associated with the presence of MSI.
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Affiliation(s)
- Marta Viana-Pereira
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
- Section of Paediatric Oncology, Institute of Cancer Research, Sutton, Surrey, United Kingdom
| | - Alicia Lee
- Section of Paediatric Oncology, Institute of Cancer Research, Sutton, Surrey, United Kingdom
| | - Sergey Popov
- Section of Paediatric Oncology, Institute of Cancer Research, Sutton, Surrey, United Kingdom
- Paediatric Oncology, Royal Marsden Hospital, Sutton, Surrey, United Kingdom
| | - Dorine A. Bax
- Section of Paediatric Oncology, Institute of Cancer Research, Sutton, Surrey, United Kingdom
| | - Safa Al-Sarraj
- Department of Clinical Neuropathology, Kings College Hospital, London, United Kingdom
| | | | - João N. Stávale
- Department of Pathology, Federal University of São Paulo, São Paulo, Brazil
| | - Darren Hargrave
- Paediatric Oncology, Royal Marsden Hospital, Sutton, Surrey, United Kingdom
| | - Chris Jones
- Section of Paediatric Oncology, Institute of Cancer Research, Sutton, Surrey, United Kingdom
- Paediatric Oncology, Royal Marsden Hospital, Sutton, Surrey, United Kingdom
- * E-mail: (RMR); (CJ)
| | - Rui M. Reis
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
- Molecular Oncology Research Center, Barretos Cancer Hospital, Barretos, Brazil
- * E-mail: (RMR); (CJ)
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11
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Goel A, Nguyen TP, Leung HCE, Nagasaka T, Rhees J, Hotchkiss E, Arnold M, Banerji P, Koi M, Kwok CT, Packham D, Lipton L, Boland CR, Ward RL, Hitchins MP. De novo constitutional MLH1 epimutations confer early-onset colorectal cancer in two new sporadic Lynch syndrome cases, with derivation of the epimutation on the paternal allele in one. Int J Cancer 2011; 128:869-78. [PMID: 20473912 DOI: 10.1002/ijc.25422] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Lynch syndrome is an autosomal dominant cancer predisposition syndrome classically caused by germline mutations of the mismatch repair genes, MLH1, MSH2, MSH6 and PMS2. Constitutional epimutations of the MLH1 gene, characterized by soma-wide methylation of a single allele of the promoter and allelic transcriptional silencing, have been identified in a subset of Lynch syndrome cases lacking a sequence mutation in MLH1. We report two individuals with no family history of colorectal cancer who developed that disease at age 18 and 20 years. In both cases, cancer had arisen because of the de novo occurrence of a constitutional MLH1 epimutation and somatic loss-of-heterozygosity of the functional allele in the tumors. We show for the first time that the epimutation in one case arose on the paternally inherited allele. Analysis of 13 tumors from seven individuals with constitutional MLH1 epimutations showed eight tumors had lost the second MLH1 allele, two tumors had a novel pathogenic missense mutation and three had retained heterozygosity. Only 1 of 12 tumors demonstrated the BRAF V600E mutation and 3 of 11 tumors harbored a mutation in KRAS. The finding that epimutations can originate on the paternal allele provides important new insights into the mechanism of origin of epimutations. It is clear that the second hit in MLH1 epimutation-associated tumors typically has a genetic not epigenetic basis. Individuals with mismatch repair-deficient cancers without the BRAF V600E mutation are candidates for germline screening for sequence or methylation changes in MLH1.
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Affiliation(s)
- Ajay Goel
- Gastrointestinal Cancer Research Laboratory, Baylor University Medical Center, Dallas, TX, USA
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12
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Raskin L, Schwenter F, Freytsis M, Tischkowitz M, Wong N, Chong G, Narod SA, Levine DA, Bogomolniy F, Aronson M, Thibodeau SN, Hunt KS, Rennert G, Gallinger S, Gruber SB, Foulkes WD. Characterization of two Ashkenazi Jewish founder mutations in MSH6 gene causing Lynch syndrome. Clin Genet 2010; 79:512-22. [PMID: 21155762 DOI: 10.1111/j.1399-0004.2010.01594.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Founder mutations are an important cause of Lynch syndrome and facilitate genetic testing in specific ethnic populations. Two putative founder mutations in MSH6 were analyzed in 2685 colorectal cancer (CRC) cases, 337 endometrial cancer (EnCa) cases and 3310 healthy controls of Ashkenazi Jewish (AJ) descent from population-based and hospital-based case–control studies in Israel, Canada and the United States. The carriers were haplotyped and the age of the mutations was estimated. MSH6*c.3984_3987dupGTCA was found in 8/2685 CRC cases, 2/337 EnCa cases, and 1/3310 controls, consistent with a high risk of CRC (odds ratio (OR) = 9.9, 95% confidence interval (CI) = 1.2–78.9, p = 0.0079) and a very high risk of EnCa (OR = 19.6, 95% CI = 1.8–217.2, p = 0.0006). MSH6*c.3959_3962delCAAG was identified in 3/2685 CRC cases, 2/337 EnCa cases and no controls. Each mutation was observed on separate conserved haplotypes. MSH6*c.3984_3987dupGTCA and MSH6*c.3959_3962delCAAG probably arose around 585 CE and 685 CE, respectively. No carriers were identified in Sephardi Jews (450 cases and 490 controls). Truncating mutations MSH6*c.3984_3987dupGTCA and MSH6*c.3959_3962delCAAG cause Lynch syndrome and are founder mutations in Ashkenazi Jews. Together with other AJ founder mutations, they contribute substantially to the incidence of CRC and EnCa and are important tools for the early diagnosis and appropriate management of AJ Lynch syndrome patients.
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Affiliation(s)
- L Raskin
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
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13
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Abstract
Mutations in DNA mismatch repair genes underlie lynch syndrome (HNPCC). Lynch syndrome resulting from mutations in MSH6 is considered to be attenuated in comparison to that caused by mutations in MLH1 and MSH2, thus more likely to be under diagnosed. In this study we report of a common mutation in the MSH6 gene in Ashkenazi Jews. Genetic counseling and diagnostic work-up for HNPCC was conducted in families who attended the high risk clinic for inherited cancer. We identified the mutation c.3984_3987dup in the MSH6 gene in 19 members of four unrelated Ashkenazi families. This mutation results in truncation of the transcript and in loss of expression of the MSH6 protein in tumors. Tumor spectrum among carriers included colon, endometrial, gastric, ovarian, urinary, and breast cancer. All but one family qualified for the Bethesda guidelines and none fulfilled the Amsterdam Criteria. Members of one family also co-inherited the c.6174delT mutation in the BRCA2 gene. The c.3984_3987dup in the MSH6 gene is a mutation leading to HNPCC among Ashkenazi Jews. This is most probably a founder mutation. In contrast to the c.1906G>C founder mutation in the MSH2 gene, tumors tend to occur later in life, and none of the families qualified for the Amsterdam criteria. c.3984_3987dup is responsible for 1/6 of the mutations identified among Ashkenazi HNPCC families in our cohort. Both mutations: c.3984_3987dup and c.1906G>C account for 61% of HNPCC Ashkenazi families in this cohort. These findings are of great importance for counseling, diagnosis, management and surveillance for Ashkenazi families with Lynch syndrome.
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14
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Screening for germline mutations of MLH1, MSH2, MSH6 and PMS2 genes in Slovenian colorectal cancer patients: implications for a population specific detection strategy of Lynch syndrome. Fam Cancer 2009; 8:421-9. [DOI: 10.1007/s10689-009-9258-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Accepted: 06/02/2009] [Indexed: 12/14/2022]
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15
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A new strategy to screen MMR genes in Lynch Syndrome: HA-CAE, MLPA and RT-PCR. Eur J Cancer 2009; 45:1485-93. [PMID: 19250818 DOI: 10.1016/j.ejca.2009.01.030] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Revised: 01/12/2009] [Accepted: 01/16/2009] [Indexed: 02/06/2023]
Abstract
AIMS Hereditary non-polyposis colon cancer (HNPCC) is an autosomal dominant disorder that is genetically heterogeneous because of underlying mutations in mismatch repair (MMR) genes, primarily MLH1, MSH2 and MSH6. One challenge to correctly diagnose HNPCC is that the large size of the causative genes makes identification of mutations both labour intensive and expensive. METHODS Our heteroduplex analysis by capillary array electrophoresis (HA-CAE) method, previously developed to increase the throughput and allow other multi-exon genes to be scanned, has been adapted for MMR genes. The altered peak patterns were then sequenced. Furthermore, the mutational scanning was completed using the Multiplex Ligation-Dependent Probe Amplification (MLPA) test in all negative HA-CAE cases, and these results were confirmed by RT-PCR. RESULTS We studied 216 individuals belonging to 100 unrelated families that met the Amsterdam I/II criteria for HNPCC. We detected 40 different variants that are classified as follows: 8 (20%) deleterious mutation, 8 (20%) unknown pathogenic significance variants and 24 (60%) coding and intronic sequence variants. Pathogenic mutations were detected in 12% of the families and about 42% of these had a deletion variant. Unknown pathogenic significance variants (UVs) affected 13% of the families. We also found 12.5% of novel polymorphisms in the rest of the variants. CONCLUDING: In short, using a combined method that includes HA-CAE, MLPA and RT-PCR, it is possible to detect the entire mutational spectrum of MMR genes. Twenty percent of the mutations found in the three genes have not been reported before. Relatives at risk will be offered predictive molecular analysis with potential exclusion of non-carriers of mutations.
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16
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Zhao YS, Hu FL, Wang F, Han B, Li DD, Li XW, Zhu S. Meta-analysis of MSH6 gene mutation frequency in colorectal and endometrial cancers. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2009; 72:690-697. [PMID: 19492230 DOI: 10.1080/15287390902841003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Studies on mutations and mutation frequencies of the MSH6 gene, which mainly focus on new types of mutations in small samples, have been published ever since the first report of MSH6 mutation in two atypical hereditary non-polyposis colorectal cancer patients. However, the results remain inconsistent. Therefore, a systematic review was conducted and a meta-analysis was undertaken to determine the frequency of MSH6 mutation in colorectal and endometrial cancers. From 27 studies, 180 cases with MSH6 mutation in a total of 3196 cases were detected. In colorectal and endometrial cancers the MSH6 mutation frequency is 7.2 and 9.6%, respectively. MSH6 mutation frequency was 10.4% in hereditary non-polyposis colorectal cancer patients, 7.1% in atypical hereditary non-polyposis colorectal cancer patients, and 5.9% in sporadic patients. The frequency of MSH6 mutation in high microsatellite instability (MSI-H) was 11.6% and in low microsatellite instability (MSI-L) cases was (13.3%), which were higher than in microsatellite stability (MSS) cases (1.7%). The mean age of the earliest onset of colorectal and endometrial cancers in MSH6 mutation carriers was 51.2 and 56.5 yr, respectively. Data suggest that the frequency of MSH6 mutation is higher in hereditary non-polyposis colorectal cancer patients than in atypical hereditary non-polyposis colorectal cancer and sporadic patients. MSH6 mutation frequency was also higher in endometrial than colorectal cancers. The mean age of earliest onset of endometrial cancer (56.5 yr) is older than for colorectal cancer (51.2 yr) in carriers of MSH6 mutation. Our results provide evidence for clinical genetic testing and counseling.
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Affiliation(s)
- Ya-shuang Zhao
- Department of Epidemiology, Public Health College, Harbin Medical University, Heilongjiang Province, People's Republic of China.
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17
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Oocyte-specific G-protein–coupled receptor 3 (GPR3): no perturbations found in 82 women with premature ovarian failure (first report). Fertil Steril 2008; 90:1269-71. [DOI: 10.1016/j.fertnstert.2007.07.1373] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Revised: 07/24/2007] [Accepted: 07/24/2007] [Indexed: 11/20/2022]
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18
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Sestini R, Provenzano A, Bacci C, Orlando C, Genuardi M, Papi L. NF2 mutation screening by denaturing high-performance liquid chromatography and high-resolution melting analysis. ACTA ACUST UNITED AC 2008; 12:311-8. [PMID: 18554169 DOI: 10.1089/gte.2007.0096] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Neurofibromatosis type 2 (NF2) is an autosomal-dominant disorder caused by mutations in the NF2 gene and predisposing to the development of nervous system. Identification of germline mutations is essential to provide appropriate genetic counseling in NF2 patients, but it represents an extremely challenging task because the vast majority of mutations are unique and spread over the entire coding sequence. Moreover, about 30% of de novo patients are indeed mosaic, and direct sequencing can undetect mutated alleles present in a minority of cells. As most screening techniques do not meet the requirements for efficient NF2 testing, we have developed a semi-automated denaturing high-performance liquid chromatography (DHPLC) method for point mutation detection combined with a multiplex ligation-dependent probe amplification approach to screen for gene rearrangements. In addition, we have evaluated high-resolution melting analysis (HRMA) as an exon scanning procedure to identify point mutations in the NF2 gene. The results obtained in 92 NF2 patients expand the NF2 mutational spectrum and indicate DHPLC and HRMA as good systems to screen for point mutations in diseases with a heterogeneous spectrum of alterations.
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Affiliation(s)
- Roberta Sestini
- Department of Clinical Physiopathology, Medical Genetics Unit, University of Florence, Firenze, Italy.
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19
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Ollila S, Bebek DD, Greenblatt M, Nyström M. Uncertain pathogenicity of MSH2
variants N127S and G322D challenges their classification. Int J Cancer 2008; 123:720-4. [DOI: 10.1002/ijc.23573] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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20
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Bai XY, Shen H. Mutational analysis of thyroid transcription factor-1 gene (TTF-1) in lung carcinomas. In Vitro Cell Dev Biol Anim 2007; 44:17-25. [PMID: 18071837 DOI: 10.1007/s11626-007-9062-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Accepted: 09/17/2007] [Indexed: 11/28/2022]
Abstract
We studied the expression and mutation of thyroid transcription factor-1 (TTF-1) gene in 92 cases of lung carcinomas comprised of lung adenocarcinoma (36 cases), squamous cell lung carcinoma (42 cases), small cell lung carcinoma (8 cases), and large cell lung carcinoma (6 cases) to investigate whether TTF-1 gene mutation predisposed to the development of lung cancer. Normal lung tissues were obtained from each of the 92 patients. The tissues served as controls. Polymerase chain reaction-single-strand conformation polymorphism, denaturing high-performance liquid chromatography, and DNA sequencing were used to analyze TTF-1 gene mutation and its relationship with the carcinogenesis of lung cancer. We detected the expression of TTF-1 protein and messenger RNA (mRNA) in paraffin-embedded lung carcinomas and their normal lung tissues by tissue microarray. TTF-1 protein and mRNA intensities were measured by Leica-Q500 MC Image Analysis System to reveal their correlation with TTF-1 mutation in lung carcinomas. TTF-1 gene missense and synonymous mutation are present in lung carcinomas with the mutation rate of 16%. TTF-1 protein and mRNA are higher in normal lung tissues than in different lung carcinomas. TTF-1 gene mutation is correlated with the loss of TTF-1 protein and mRNA. The analyses of TTF-1 gene missense mutation and synonymous mutation and the loss of TTF-1 protein and mRNA can be regarded as the important indexes of molecular pathology of lung carcinoma.
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Affiliation(s)
- Xiao Yan Bai
- Department of Pathology, School of Basic Medical Science, Southern Medical University, Guangzhou, Guangdong Province, People's Republic of China.
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21
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Hitchins MP, Wong JJL, Suthers G, Suter CM, Martin DIK, Hawkins NJ, Ward RL. Inheritance of a cancer-associated MLH1 germ-line epimutation. N Engl J Med 2007; 356:697-705. [PMID: 17301300 DOI: 10.1056/nejmoa064522] [Citation(s) in RCA: 283] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Persons who have hypermethylation of one allele of MLH1 in somatic cells throughout the body (a germ-line epimutation) have a predisposition for the development of cancer in a pattern typical of hereditary nonpolyposis colorectal cancer. By studying the families of two such persons, we found evidence that the epimutation was transmitted from a mother to her son but was erased in his spermatozoa. The affected maternal allele was inherited by three other siblings from these two families, but in those offspring the allele had reverted to the normal active state. These findings demonstrate a novel pattern of inheritance of cancer susceptibility and are consistent with transgenerational epigenetic inheritance.
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Affiliation(s)
- Megan P Hitchins
- Department of Medical Oncology, St. Vincent's Hospital, Sydney, Australia
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22
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Ekstrøm PO, Bjørheim J. Evaluation of sieving matrices used to separate alleles by cycling temperature capillary electrophoresis. Electrophoresis 2006; 27:1878-85. [PMID: 16619298 DOI: 10.1002/elps.200500642] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Denaturing CE (DCE) is a powerful tool for analysis of DNA variation. The development of commercial multi-CE instruments allows large-scale studies of DNA variation (many samples and many fragments). However, the cost of consumables like capillary arrays and sieving matrix might limit the use of DCE in such studies. Thus, we have tested 72 different in-house formulated sieving matrices' ability to suppress EOF and separate PCR-amplified alleles with the DCE variant, cycling temperature CE (CTCE). The data herein demonstrate that alleles can be baseline-separated by use of PVP and poly(N,N-dimethyl acrylamide) polymers at various percentages and pH. Allele separation by CTCE is matrix-independent and consequently applicable to any capillary instrument used for DNA separation. Formulation of sieving matrix for CTCE was done by dissolving appropriate amount of polymer powder into the running buffers. Allele separation was observed at different pH (7.5-8.5), concentrations and molecular size of the polymer, without compromising the separation and reproducibility. Finally, the cost reduction of homemade matrices is more than 1000-fold as compared to commercial sieving matrices.
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Affiliation(s)
- Per Olaf Ekstrøm
- Department of Surgical Oncology, The Norwegian Radium Hospital, Oslo, Norway.
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23
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Mori S, Sugahara K, Uemura A, Akamatsu N, Tutsumi R, Kuroki T, Hirakata Y, Atogami S, Hasegawa H, Yamada Y, Kamihira S. Rapid, Simple, and Accurate Detection of K-ras Mutations From Body Fluids Using Real-Time PCR and DNA Melting Curve Analysis. Lab Med 2006. [DOI: 10.1309/6507kah8ev592mj4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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