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Alenezi WM, Fierheller CT, Serruya C, Revil T, Oros KK, Subramanian DN, Bruce J, Spiegelman D, Pugh T, Campbell IG, Mes-Masson AM, Provencher D, Foulkes WD, Haffaf ZE, Rouleau G, Bouchard L, Greenwood CMT, Ragoussis J, Tonin PN. Genetic analyses of DNA repair pathway associated genes implicate new candidate cancer predisposing genes in ancestrally defined ovarian cancer cases. Front Oncol 2023; 13:1111191. [PMID: 36969007 PMCID: PMC10030840 DOI: 10.3389/fonc.2023.1111191] [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: 11/29/2022] [Accepted: 02/06/2023] [Indexed: 03/29/2023] Open
Abstract
Not all familial ovarian cancer (OC) cases are explained by pathogenic germline variants in known risk genes. A candidate gene approach involving DNA repair pathway genes was applied to identify rare recurring pathogenic variants in familial OC cases not associated with known OC risk genes from a population exhibiting genetic drift. Whole exome sequencing (WES) data of 15 OC cases from 13 families tested negative for pathogenic variants in known OC risk genes were investigated for candidate variants in 468 DNA repair pathway genes. Filtering and prioritization criteria were applied to WES data to select top candidates for further analyses. Candidates were genotyped in ancestry defined study groups of 214 familial and 998 sporadic OC or breast cancer (BC) cases and 1025 population-matched controls and screened for additional carriers in 605 population-matched OC cases. The candidate genes were also analyzed in WES data from 937 familial or sporadic OC cases of diverse ancestries. Top candidate variants in ERCC5, EXO1, FANCC, NEIL1 and NTHL1 were identified in 5/13 (39%) OC families. Collectively, candidate variants were identified in 7/435 (1.6%) sporadic OC cases and 1/566 (0.2%) sporadic BC cases versus 1/1025 (0.1%) controls. Additional carriers were identified in 6/605 (0.9%) OC cases. Tumour DNA from ERCC5, NEIL1 and NTHL1 variant carriers exhibited loss of the wild-type allele. Carriers of various candidate variants in these genes were identified in 31/937 (3.3%) OC cases of diverse ancestries versus 0-0.004% in cancer-free controls. The strategy of applying a candidate gene approach in a population exhibiting genetic drift identified new candidate OC predisposition variants in DNA repair pathway genes.
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Affiliation(s)
- Wejdan M. Alenezi
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Cancer Research Program, Centre for Translational Biology, The Research Institute of McGill University Health Centre, Montreal, QC, Canada
- Department of Medical Laboratory Technology, Taibah University, Medina, Saudi Arabia
| | - Caitlin T. Fierheller
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Cancer Research Program, Centre for Translational Biology, The Research Institute of McGill University Health Centre, Montreal, QC, Canada
| | - Corinne Serruya
- Cancer Research Program, Centre for Translational Biology, The Research Institute of McGill University Health Centre, Montreal, QC, Canada
| | - Timothée Revil
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- McGill Genome Centre, McGill University, Montreal, QC, Canada
| | - Kathleen K. Oros
- Lady Davis Institute for Medical Research of the Jewish General Hospital, Montreal, QC, Canada
| | - Deepak N. Subramanian
- Cancer Genetics Laboratory, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
| | - Jeffrey Bruce
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
| | - Dan Spiegelman
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Trevor Pugh
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Ontario Institute for Cancer Research, Toronto, ON, Canada
| | - Ian G. Campbell
- Cancer Genetics Laboratory, Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, VIC, Australia
| | - Anne-Marie Mes-Masson
- Centre de recherche du Centre hospitalier de l’Université de Montréal and Institut du cancer de Montréal, Montreal, QC, Canada
- Departement of Medicine, Université de Montréal, Montreal, QC, Canada
| | - Diane Provencher
- Centre de recherche du Centre hospitalier de l’Université de Montréal and Institut du cancer de Montréal, Montreal, QC, Canada
- Division of Gynecologic Oncology, Université de Montréal, Montreal, QC, Canada
| | - William D. Foulkes
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Cancer Research Program, Centre for Translational Biology, The Research Institute of McGill University Health Centre, Montreal, QC, Canada
- Lady Davis Institute for Medical Research of the Jewish General Hospital, Montreal, QC, Canada
- Department of Medical Genetics, McGill University Health Centre, Montreal, QC, Canada
- Department of Medicine, McGill University, Montreal, QC, Canada
- Gerald Bronfman Department of Oncology, McGill University, Montreal, QC, Canada
| | - Zaki El Haffaf
- Centre de recherche du Centre hospitalier de l’Université de Montréal and Institut du cancer de Montréal, Montreal, QC, Canada
- Service de Médecine Génique, Centre Hospitalier de l’Université de Montréal, Montreal, QC, Canada
| | - Guy Rouleau
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Luigi Bouchard
- Department of Biochemistry and Functional Genomics, Université de Sherbrooke, Sherbrooke, QC, Canada
- Department of Medical Biology, Centres intégrés universitaires de santé et de services sociaux du Saguenay-Lac-Saint-Jean hôpital Universitaire de Chicoutimi, Saguenay, QC, Canada
- Centre de Recherche du Centre hospitalier l’Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Celia M. T. Greenwood
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Lady Davis Institute for Medical Research of the Jewish General Hospital, Montreal, QC, Canada
- Gerald Bronfman Department of Oncology, McGill University, Montreal, QC, Canada
- Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada
| | - Jiannis Ragoussis
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- McGill Genome Centre, McGill University, Montreal, QC, Canada
| | - Patricia N. Tonin
- Department of Human Genetics, McGill University, Montreal, QC, Canada
- Cancer Research Program, Centre for Translational Biology, The Research Institute of McGill University Health Centre, Montreal, QC, Canada
- Department of Medicine, McGill University, Montreal, QC, Canada
- *Correspondence: Patricia N. Tonin,
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Alenezi WM, Fierheller CT, Revil T, Serruya C, Mes-Masson AM, Foulkes WD, Provencher D, El Haffaf Z, Ragoussis J, Tonin PN. Case Review: Whole-Exome Sequencing Analyses Identify Carriers of a Known Likely Pathogenic Intronic BRCA1 Variant in Ovarian Cancer Cases Clinically Negative for Pathogenic BRCA1 and BRCA2 Variants. Genes (Basel) 2022; 13:genes13040697. [PMID: 35456503 PMCID: PMC9032308 DOI: 10.3390/genes13040697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/01/2022] [Accepted: 04/14/2022] [Indexed: 12/04/2022] Open
Abstract
Background: Detecting pathogenic intronic variants resulting in aberrant splicing remains a challenge in routine genetic testing. We describe germline whole-exome sequencing (WES) analyses and apply in silico predictive tools of familial ovarian cancer (OC) cases reported clinically negative for pathogenic BRCA1 and BRCA2 variants. Methods: WES data from 27 familial OC cases reported clinically negative for pathogenic BRCA1 and BRCA2 variants and 53 sporadic early-onset OC cases were analyzed for pathogenic variants in BRCA1 or BRCA2. WES data from carriers of pathogenic BRCA1 or BRCA2 variants were analyzed for pathogenic variants in 10 other OC predisposing genes. Loss of heterozygosity analysis was performed on tumor DNA from variant carriers. Results: BRCA1 c.5407-25T>A intronic variant, identified in two affected sisters and one sporadic OC case, is predicted to create a new splice effecting transcription of BRCA1. WES data from BRCA1 c.5407-25T>A carriers showed no evidence of pathogenic variants in other OC predisposing genes. Sequencing the tumor DNA from the variant carrier showed complete loss of the wild-type allele. Conclusions: The findings support BRCA1 c.5407-25T>A as a likely pathogenic variant and highlight the importance of investigating intronic sequences as causal variants in OC families where the involvement of BRCA1 is highly suggestive.
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Affiliation(s)
- Wejdan M. Alenezi
- Department of Human Genetics, McGill University, Montreal, QC H3A 0C7, Canada; (W.M.A.); (C.T.F.); (T.R.); (W.D.F.); (J.R.)
- Cancer Research Program, Centre for Translational Biology, The Research Institute of McGill University Health Centre, Montreal, QC H4A 3J1, Canada;
- Department of Medical Laboratory Technology, Taibah University, Medina 42353, Saudi Arabia
| | - Caitlin T. Fierheller
- Department of Human Genetics, McGill University, Montreal, QC H3A 0C7, Canada; (W.M.A.); (C.T.F.); (T.R.); (W.D.F.); (J.R.)
- Cancer Research Program, Centre for Translational Biology, The Research Institute of McGill University Health Centre, Montreal, QC H4A 3J1, Canada;
| | - Timothée Revil
- Department of Human Genetics, McGill University, Montreal, QC H3A 0C7, Canada; (W.M.A.); (C.T.F.); (T.R.); (W.D.F.); (J.R.)
- McGill Genome Centre, McGill University, Montreal, QC H3A 0G1, Canada
| | - Corinne Serruya
- Cancer Research Program, Centre for Translational Biology, The Research Institute of McGill University Health Centre, Montreal, QC H4A 3J1, Canada;
| | - Anne-Marie Mes-Masson
- Département de Médecine, Université de Montréal, Montreal, QC H3T 1J4, Canada;
- Institut du Cancer de Montréal, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montreal, QC H2X 0A9, Canada; (D.P.); (Z.E.H.)
| | - William D. Foulkes
- Department of Human Genetics, McGill University, Montreal, QC H3A 0C7, Canada; (W.M.A.); (C.T.F.); (T.R.); (W.D.F.); (J.R.)
- Cancer Research Program, Centre for Translational Biology, The Research Institute of McGill University Health Centre, Montreal, QC H4A 3J1, Canada;
- Lady Davis Institute for Medical Research of the Jewish General Hospital, Montreal, QC H3T 1E2, Canada
- Department of Medical Genetics, McGill University Health Centre, Montreal, QC H3H 1P3, Canada
- Department of Medicine, McGill University, Montreal, QC H4A 3J1, Canada
- Gerald Bronfman Department of Oncology, McGill University, Montreal, QC H3A 1G5, Canada
| | - Diane Provencher
- Institut du Cancer de Montréal, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montreal, QC H2X 0A9, Canada; (D.P.); (Z.E.H.)
- Division of Gynecologic Oncology, Université de Montréal, Montreal, QC H4A 3J1, Canada
| | - Zaki El Haffaf
- Institut du Cancer de Montréal, Centre de Recherche du Centre Hospitalier de l’Université de Montréal, Montreal, QC H2X 0A9, Canada; (D.P.); (Z.E.H.)
- Service de Médecine Génique, Centre Hospitalier de l’Université de Montréal, Montreal, QC H2X 0A9, Canada
| | - Jiannis Ragoussis
- Department of Human Genetics, McGill University, Montreal, QC H3A 0C7, Canada; (W.M.A.); (C.T.F.); (T.R.); (W.D.F.); (J.R.)
- McGill Genome Centre, McGill University, Montreal, QC H3A 0G1, Canada
| | - Patricia N. Tonin
- Department of Human Genetics, McGill University, Montreal, QC H3A 0C7, Canada; (W.M.A.); (C.T.F.); (T.R.); (W.D.F.); (J.R.)
- Cancer Research Program, Centre for Translational Biology, The Research Institute of McGill University Health Centre, Montreal, QC H4A 3J1, Canada;
- Department of Medicine, McGill University, Montreal, QC H4A 3J1, Canada
- Correspondence: ; Tel.: +1-(514)-934-1934 (ext. 44069)
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Li J, Wang P, Zhang C, Han S, Xiao H, Liu Z, Wang X, Liu W, Wei B, Ma J, Li H, Guo Y. Characterization of Synonymous BRCA1:c.132C>T as a Pathogenic Variant. Front Oncol 2022; 11:812656. [PMID: 35087763 PMCID: PMC8789006 DOI: 10.3389/fonc.2021.812656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 12/08/2021] [Indexed: 11/26/2022] Open
Abstract
Breast cancer gene 1 (BRCA1) and BRCA2 are tumor suppressors involved in DNA damage response and repair. Carriers of germline pathogenic or likely pathogenic variants in BRCA1 or BRCA2 have significantly increased lifetime risks of breast cancer, ovarian cancer, and other cancer types; this phenomenon is known as hereditary breast and ovarian cancer (HBOC) syndrome. Accurate interpretation of BRCA1 and BRCA2 variants is important not only for disease management in patients, but also for determining preventative measures for their families. BRCA1:c.132C>T (p.Cys44=) is a synonymous variant recorded in the ClinVar database with “conflicting interpretations of its pathogenicity”. Here, we report our clinical tests in which we identified this variant in two unrelated patients, both of whom developed breast cancer at an early age with ovarian presentation a few years later and had a family history of relevant cancers. Minigene assay showed that this change caused a four-nucleotide loss at the end of exon 3, resulting in a truncated p.Cys44Tyrfs*5 protein. Reverse transcription-polymerase chain reaction identified two fragments (123 and 119 bp) using RNA isolated from patient blood samples, in consistency with the results of the minigene assay. Collectively, we classified BRCA1:c.132C>T (p.Cys44=) as a pathogenic variant, as evidenced by functional studies, RNA analysis, and the patients’ family histories. By analyzing variants recorded in the BRCA Exchange database, we found synonymous changes at the ends of exons could potentially influence splicing; meanwhile, current in silico tools could not predict splicing changes efficiently if the variants were in the middle of an exon, or in the deep intron region. Future studies should attempt to identify variants that influence gene expression and post-transcription modifications to improve our understanding of BRCA1 and BRCA2, as well as their related cancers.
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Affiliation(s)
- Jun Li
- Department of Molecular Pathology, The Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, China.,Henan Key Laboratory of Molecular Pathology, Zhengzhou, China.,Henan International Joint Laboratory of Cancer Genetics, Zhengzhou, China
| | - Ping Wang
- Department of Pathophysiology, School of Basic Medical Science, Zhengzhou University, Zhengzhou, China
| | - Cuiyun Zhang
- Department of Molecular Pathology, The Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, China.,Henan Key Laboratory of Molecular Pathology, Zhengzhou, China.,Henan International Joint Laboratory of Cancer Genetics, Zhengzhou, China
| | - Sile Han
- Department of Molecular Pathology, The Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, China
| | - Han Xiao
- Department of Breast Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zhiyuan Liu
- Amoy Diagnostics Co., Ltd. (AmoyDx), Xiamen, China
| | - Xiaoyan Wang
- Department of Molecular Pathology, The Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, China.,Henan Key Laboratory of Molecular Pathology, Zhengzhou, China.,Henan International Joint Laboratory of Cancer Genetics, Zhengzhou, China
| | - Weiling Liu
- Department of Medical Oncology, The Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzou, China
| | - Bing Wei
- Department of Molecular Pathology, The Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, China.,Henan Key Laboratory of Molecular Pathology, Zhengzhou, China.,Henan International Joint Laboratory of Cancer Genetics, Zhengzhou, China
| | - Jie Ma
- Department of Molecular Pathology, The Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, China.,Henan Key Laboratory of Molecular Pathology, Zhengzhou, China.,Henan International Joint Laboratory of Cancer Genetics, Zhengzhou, China
| | - Hongle Li
- Department of Molecular Pathology, The Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, China
| | - Yongjun Guo
- Department of Molecular Pathology, The Affiliated Cancer Hospital of Zhengzhou University and Henan Cancer Hospital, Zhengzhou, China.,Henan Key Laboratory of Molecular Pathology, Zhengzhou, China.,Henan International Joint Laboratory of Cancer Genetics, Zhengzhou, China
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Arshad S, Ishaque I, Mumtaz S, Rashid MU, Malkani N. In-Silico Analyses of Nonsynonymous Variants in the BRCA1 Gene. Biochem Genet 2021; 59:1506-1526. [PMID: 33945048 DOI: 10.1007/s10528-021-10074-7] [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: 06/30/2020] [Accepted: 04/22/2021] [Indexed: 10/21/2022]
Abstract
BReast CAncer gene 1 (BRCA1)-a tumor suppressor gene plays an important role in the DNA repair mechanism. Several BRCA1 variants perturb its structure and function, including synonymous and nonsynonymous single nucleotide polymorphisms (SNPs). In the present study, we performed in-silico analyses of nonsynonymous SNPs (nsSNPs) of the BRCA1 gene. In total, 122 nsSNPs were retrieved from the NCBI SNP database and in-silico analyses were performed using computational prediction tools: SIFT, PROVEAN, Mutation Taster, PolyPhen-2, MutPred, and ConSurf. Of these tools, SIFT, PROVEAN, and Mutation Taster predicted 61 out of 122 nsSNPs as "damaging", based on structural homology analysis. PolyPhen-2 classified 22 nsSNPs as "probably damaging". These nsSNPs were further analyzed by MutPred to predict basic molecular mechanisms of amino acid alteration. ConSurf analysis predicted eleven conserved amino acid residues with structural and functional consequences. We identified five amino acid residues in the RING finger domain (L22, C39, H41, C44, and C47) and two in the BRCT domain (P1771 and I1707) with the potential to deter the BRCA1 protein function. This study provides insights into the effect of nsSNPs and amino acid substitutions in BRCA1.
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Affiliation(s)
- Sidra Arshad
- Department of Zoology, GC University, Lahore, Pakistan
| | - Irfan Ishaque
- Department of Zoology, GC University, Lahore, Pakistan
| | - Sidra Mumtaz
- Department of Zoology, GC University, Lahore, Pakistan
| | - Muhammad Usman Rashid
- Department of Basic Sciences Research, Shaukat Khanum Memorial Cancer Hospital and Research Centre (SKMCH&RC), Lahore, Pakistan
| | - Naila Malkani
- Department of Zoology, GC University, Lahore, Pakistan.
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