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Møller NB, Boonen DS, Feldner ES, Hao Q, Larsen M, Lænkholm AV, Borg Å, Kvist A, Törngren T, Jensen UB, Boonen SE, Thomassen M, Terkelsen T. Validation of the BOADICEA model for predicting the likelihood of carrying pathogenic variants in eight breast and ovarian cancer susceptibility genes. Sci Rep 2023; 13:8536. [PMID: 37237042 PMCID: PMC10220031 DOI: 10.1038/s41598-023-35755-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 05/23/2023] [Indexed: 05/28/2023] Open
Abstract
BOADICEA is a comprehensive risk prediction model for breast and/or ovarian cancer (BC/OC) and for carrying pathogenic variants (PVs) in cancer susceptibility genes. In addition to BRCA1 and BRCA2, BOADICEA version 6 includes PALB2, CHEK2, ATM, BARD1, RAD51C and RAD51D. To validate its predictions for these genes, we conducted a retrospective study including 2033 individuals counselled at clinical genetics departments in Denmark. All counselees underwent comprehensive genetic testing by next generation sequencing on suspicion of hereditary susceptibility to BC/OC. Likelihoods of PVs were predicted from information about diagnosis, family history and tumour pathology. Calibration was examined using the observed-to-expected ratio (O/E) and discrimination using the area under the receiver operating characteristics curve (AUC). The O/E was 1.11 (95% CI 0.97-1.26) for all genes combined. At sub-categories of predicted likelihood, the model performed well with limited misestimation at the extremes of predicted likelihood. Discrimination was acceptable with an AUC of 0.70 (95% CI 0.66-0.74), although discrimination was better for BRCA1 and BRCA2 than for the other genes in the model. This suggests that BOADICEA remains a valid decision-making aid for determining which individuals to offer comprehensive genetic testing for hereditary susceptibility to BC/OC despite suboptimal calibration for individual genes in this population.
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Affiliation(s)
- Nanna Bæk Møller
- Department of Clinical Genetics, Aarhus University Hospital, Brendstrupgårdsvej 21, 8200, Aarhus N, Denmark
| | - Desirée Sofie Boonen
- Department of Clinical Genetics, Odense University Hospital, J. B. Winsløws Vej 4, 5000, Odense, Denmark
| | - Elisabeth Simone Feldner
- Department of Clinical Genetics, Odense University Hospital, J. B. Winsløws Vej 4, 5000, Odense, Denmark
| | - Qin Hao
- Department of Clinical Genetics, Odense University Hospital, J. B. Winsløws Vej 4, 5000, Odense, Denmark
| | - Martin Larsen
- Department of Clinical Genetics, Odense University Hospital, J. B. Winsløws Vej 4, 5000, Odense, Denmark
| | - Anne-Vibeke Lænkholm
- Department of Surgical Pathology, Zealand University Hospital, Roskilde, Denmark
| | - Åke Borg
- Division of Oncology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Anders Kvist
- Division of Oncology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Therese Törngren
- Division of Oncology, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Uffe Birk Jensen
- Department of Clinical Genetics, Aarhus University Hospital, Brendstrupgårdsvej 21, 8200, Aarhus N, Denmark
| | - Susanne Eriksen Boonen
- Department of Clinical Genetics, Odense University Hospital, J. B. Winsløws Vej 4, 5000, Odense, Denmark
| | - Mads Thomassen
- Department of Clinical Genetics, Odense University Hospital, J. B. Winsløws Vej 4, 5000, Odense, Denmark.
| | - Thorkild Terkelsen
- Department of Clinical Genetics, Aarhus University Hospital, Brendstrupgårdsvej 21, 8200, Aarhus N, Denmark.
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Jasiak A, Koczkowska M, Stukan M, Wydra D, Biernat W, Izycka-Swieszewska E, Buczkowski K, Eccles MR, Walker L, Wasag B, Ratajska M. Analysis of BRCA1 and BRCA2 alternative splicing in predisposition to ovarian cancer. Exp Mol Pathol 2023; 130:104856. [PMID: 36791903 DOI: 10.1016/j.yexmp.2023.104856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 01/25/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023]
Abstract
BACKGROUND The mRNA splicing is regulated on multiple levels, resulting in the proper distribution of genes' transcripts in each cell and maintaining cell homeostasis. At the same time, the expression of alternative transcripts can change in response to underlying genetic variants, often missed during routine diagnostics. AIM The main aim of this study was to define the frequency of aberrant splicing in BRCA1 and BRCA2 genes in blood RNA extracted from ovarian cancer patients who were previously found negative for the presence of pathogenic alterations in the 25 most commonly analysed ovarian cancer genes, including BRCA1 and BRCA2. MATERIAL AND METHODS Frequency and spectrum of splicing alterations in BRCA1 and BRCA2 genes were analysed in blood RNA from 101 ovarian cancer patients and healthy controls (80 healthy women) using PCR followed by gel electrophoresis and Sanger sequencing. The expression of splicing events was examined using RT-qPCR. RESULTS We did not identify any novel, potentially pathogenic splicing alterations. Nevertheless, we detected six naturally occurring transcripts, named BRCA1ΔE9-10, BRCA1ΔE11, BRCA1ΔE11q, and BRCA2ΔE3, BRCA2ΔE12 and BRCA2ΔE17-18 of which three (BRCA1ΔE11q, BRCA1ΔE11 and BRCA2ΔE3) were significantly higher expressed in the ovarian cancer cohort than in healthy controls (p ≤ 0.0001). CONCLUSIONS This observation indicates that the upregulation of selected naturally occurring transcripts can be stimulated by non-genetic mechanisms and be a potential systemic response to disease progression and/or treatment. However, this hypothesis requires further examination.
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Affiliation(s)
- Anna Jasiak
- Department of Biology and Medical Genetics, Medical University of Gdansk, Gdansk, Poland.
| | - Magdalena Koczkowska
- 3P Medicine Laboratory, Medical University of Gdansk, Gdansk, Poland; Department of Biology and Pharmaceutical Botany, Medical University of Gdansk, Gdansk, Poland
| | - Maciej Stukan
- Department of Gynecologic Oncology, Gdynia Oncology Center, Pomeranian Hospitals, Gdynia, Poland; Department Oncological Propedeutics, Medical University of Gdansk, Gdansk, Poland
| | - Dariusz Wydra
- Department of Gynaecology, Gynaecological Oncology and Gynaecological Endocrinology, Medical University of Gdansk, Gdansk, Poland
| | - Wojciech Biernat
- Department of Pathology, Medical University of Gdansk, Gdansk, Poland
| | | | - Kamil Buczkowski
- Department of Pathology & Neuropathology, Medical University of Gdansk, Gdansk, Poland
| | - Michael R Eccles
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Logan Walker
- Department of Pathology and Biomedical Science, University of Otago, Christchurch, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand
| | - Bartosz Wasag
- Department of Biology and Medical Genetics, Medical University of Gdansk, Gdansk, Poland; Laboratory of Clinical Genetics, University Clinical Centre, Gdansk, Poland
| | - Magdalena Ratajska
- Department of Biology and Medical Genetics, Medical University of Gdansk, Gdansk, Poland; Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, Auckland, New Zealand.
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3
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Gallardo-Rincón D, Montes-Servín E, Alamilla-García G, Montes-Servín E, Bahena-González A, Cetina-Pérez L, Morales Vásquez F, Cano-Blanco C, Coronel-Martínez J, González-Ibarra E, Espinosa-Romero R, María Alvarez-Gómez R, Pedroza-Torres A, Castro-Eguiluz D. Clinical Benefits of Olaparib in Mexican Ovarian Cancer Patients With Founder Mutation BRCA1-Del ex9-12. Front Genet 2022; 13:863956. [PMID: 35734436 PMCID: PMC9207274 DOI: 10.3389/fgene.2022.863956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 05/02/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Ovarian cancer (OC) is gynecologic cancer with the highest mortality rate. It is estimated that 13–17% of ovarian cancers are due to heritable mutations in BRCA1 and BRCA2. The BRCA1 (BRCA1-Del ex9-12) Mexican founder mutation is responsible for 28–35% of the cases with ovarian cancer. The aim was to describe the PFS of OC patients treated with olaparib, emphasizing patients carrying the Mexican founder mutation (BRCA1-Del ex9-12). Methods: In this observational study, of 107 patients with BRCAm, 35 patients were treated with olaparib from November 2016 to May 2021 at the Ovarian Cancer Program (COE) of Mexico; patient information was extracted from electronic medical records. Results: Of 311 patients, 107 (34.4%) were with BRCAm; 71.9% (77/107) were with BRCA1, of which 27.3% (21/77) were with BRCA1-Del ex9-12, and 28.1% (30/107) were with BRCA2 mutations. Only 35 patients received olaparib treatment, and the median follow-up was 12.87 months. The PFS of BRCA1-Del ex9-12 was NR (non-reach); however, 73% of the patients received the treatment at 36 vs. 11.59 months (95% CI; 10.43–12.75) in patients with other BRCAm (p = 0.008). Almost 50% of patients required dose reduction due to toxicity; the most frequent adverse events were hematological in 76.5% and gastrointestinal in 4%. Conclusion: Mexican OC BRCA1-Del ex9-12 patients treated with olaparib had a significant increase in PFS regardless of the line of treatment compared to other mutations in BRCA.
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Affiliation(s)
- Dolores Gallardo-Rincón
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- *Correspondence: Dolores Gallardo-Rincón,
| | - Edgar Montes-Servín
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Gabriela Alamilla-García
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Elizabeth Montes-Servín
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Antonio Bahena-González
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Lucely Cetina-Pérez
- Department of Clinical Research and Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Cervical Cancer Program (Micaela), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Flavia Morales Vásquez
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Claudia Cano-Blanco
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Jaime Coronel-Martínez
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Ernesto González-Ibarra
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Raquel Espinosa-Romero
- Ovarian and Endometrial Cancer Program (COE), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Department of Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Rosa María Alvarez-Gómez
- Department of Clinical Research and Medical Oncology, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Hereditary Cancer Clinic, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
| | - Abraham Pedroza-Torres
- Hereditary Cancer Clinic, Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Catedrático CONACYT, Instituto Nacional de Cancerología, Mexico City, Mexico
| | - Denisse Castro-Eguiluz
- Cervical Cancer Program (Micaela), Instituto Nacional de Cancerología (INCan), Mexico City, Mexico
- Catedrático CONACYT, Instituto Nacional de Cancerología, Mexico City, Mexico
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4
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Fan L, Yin P, Xu Z. The genetic basis of sudden death in young people - Cardiac and non-cardiac. Gene 2022; 810:146067. [PMID: 34843881 DOI: 10.1016/j.gene.2021.146067] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/25/2021] [Accepted: 11/16/2021] [Indexed: 11/04/2022]
Abstract
Sudden death is one of the major causes of death in young adults. Sudden death could be a result from both genetic and environmental or acquired factors. Understanding the genetic etiology is crucial to prevent preventable sudden death for those who are not aware of their genetic condition. In fact, the spectrum of causes of sudden death is complex and varied. In this study, we reviewed the genes that are associated with multiple causes of sudden death in terms of both sudden cardiac death and sudden noncardiac death. A summary of genetic risk factors of the major causes of genetic relevant sudden death is also provided. We believe this review could benefit the researchers who are interested in sudden death genetic studies or the young people who are concerning about their own risk on sudden death.
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Affiliation(s)
- Li Fan
- Department of Cardiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, China
| | - Ping Yin
- Department of Cardiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, China
| | - Zuojun Xu
- Department of Cardiology, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, China.
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5
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Gene Panel Testing for Breast Cancer Reveals Differential Effect of Prior BRCA1/2 Probability. Cancers (Basel) 2021; 13:cancers13164154. [PMID: 34439310 PMCID: PMC8394249 DOI: 10.3390/cancers13164154] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 08/09/2021] [Accepted: 08/16/2021] [Indexed: 12/25/2022] Open
Abstract
Whilst panel testing of an extended group of genes including BRCA1/2 is commonplace, these studies have not been subdivided by histiotype or by a priori BRCA1/2 probability. Patients with a breast cancer diagnosis undergoing extended panel testing were assessed for frequency of actionable variants in breast cancer genes other than BRCA1/2 by histiotype and Manchester score (MS) to reflect a priori BRCA1/2 likelihood. Rates were adjusted by prior testing for BRCA1/2 in an extended series. 95/1398 (6.3%) who underwent panel testing were found to be positive for actionable non-BRCA1/2 breast/ovarian cancer genes (ATM, BARD1, CDH1, CHEK2, PALB2, PTEN, RAD51C, RAD51D, TP53). As expected, PALB2, CHEK2 and ATM were predominant with 80-(5.3%). The highest rate occurred in Grade-3 ER+/HER2- breast cancers-(9.6%). Rates of non-BRCA actionable genes was fairly constant over all likelihoods of BRCA1/2 but adjusted rates were three times higher with MS < 9 (BRCA1/2 = 1.5%, other = 4.7%), but was only 1.6% compared to 79.3% with MS ≥ 40. Although rates of detection of non-BRCA actionable genes are relatively constant across BRCA1/2 likelihoods this disguises an overall adjusted low frequency in high-likelihood families which have been heavily pre-tested for BRCA1/2. Any loss of detection sensitivity for BRCA1/2 actionable variants in breast cancer panels should lead to bespoke BRCA1/2 testing being conducted first.
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6
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BRCA1 and BRCA2 whole cDNA analysis in unsolved hereditary breast/ovarian cancer patients. Cancer Genet 2021; 258-259:10-17. [PMID: 34237702 DOI: 10.1016/j.cancergen.2021.06.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 06/04/2021] [Accepted: 06/09/2021] [Indexed: 12/31/2022]
Abstract
Germline pathogenic variants in BRCA1 and BRCA2 genes (BRCA1/2) explain an important fraction of hereditary breast/ovarian cancer (HBOC) cases. Genetic testing generally involves examining coding regions and exon/intron boundaries, thus the frequency of deleterious variants in non-coding regions is unknown. Here we analysed BRCA1/2 whole cDNA in a large cohort of 320 unsolved high-risk HBOC cases in order to identify potential splicing alterations explained by variants in BRCA1/2 deep intronic regions. Whole RNA splicing profiles were analysed by RT-PCR using Sanger sequencing or high-resolution electrophoresis in a QIAxcel instrument. Known predominant BRCA1/2 alternative splicing events were detected, together with two novel events BRCA1 ▼21 and BRCA2 Δ18q_27p. BRCA2 exon 3 skipping was detected in one patient (male) affected with breast cancer, caused by a known Portuguese founder mutation (c.156_157insAluYa5). An altered BRCA2 splicing pattern was detected in three patients, consisting in the up-regulation of ▼20A, Δ22 and ▼20A+Δ22 transcripts. In silico analysis and semi-quantitative data identified the polymorphism BRCA2 c.8755-66T>C as a potential modifier of Δ22 levels. Our findings suggest that mRNA alterations in BRCA1/2 caused by deep intronic variants are rare in Spanish population. However, RNA analysis complements DNA-based strategies allowing the identification of alterations that could go undetected by conventional testing.
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7
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Woodward ER, van Veen EM, Evans DG. From BRCA1 to Polygenic Risk Scores: Mutation-Associated Risks in Breast Cancer-Related Genes. Breast Care (Basel) 2021; 16:202-213. [PMID: 34248461 DOI: 10.1159/000515319] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 02/16/2021] [Indexed: 12/12/2022] Open
Abstract
Background There has been huge progress over the last 30 years in identifying the familial component of breast cancer. Summary Currently around 20% is explained by the high-risk genes BRCA1 and BRCA2, a further 2% by other high-penetrance genes, and around 5% by the moderate risk genes ATM and CHEK2. In contrast, the more than 300 low-penetrance single-nucleotide polymorphisms (SNP) now account for around 28% and they are predicted to account for most of the remaining 45% yet to be found. Even for high-risk genes which confer a 40-90% risk of breast cancer, these SNP can substantially affect the level of breast cancer risk. Indeed, the strength of family history and hormonal and reproductive factors is very important in assessing risk even for a BRCA carrier. The risks of contralateral breast cancer are also affected by SNP as well as by the presence of high or moderate risk genes. Genetic testing using gene panels is now commonplace. Key-Messages There is a need for a more parsimonious approach to panels only testing those genes with a definite 2-fold increased risk and only testing those genes with challenging management implications, such as CDH1 and TP53, when there is strong clinical indication to do so. Testing of SNP alongside genes is likely to provide a more accurate risk assessment.
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Affiliation(s)
- Emma R Woodward
- Manchester Centre for Genomic Medicine, Manchester University Hospitals NHS Foundation Trust, Manchester, United Kingdom.,Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - Elke M van Veen
- Manchester Centre for Genomic Medicine, Manchester University Hospitals NHS Foundation Trust, Manchester, United Kingdom.,Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom
| | - D Gareth Evans
- Manchester Centre for Genomic Medicine, Manchester University Hospitals NHS Foundation Trust, Manchester, United Kingdom.,Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, United Kingdom.,PREVENT Breast Cancer Prevention Centre, Nightingale Centre, Manchester Universities Foundation Trust, Wythenshawe Hospital, Manchester, United Kingdom.,Manchester Breast Centre, Manchester Cancer Research Centre, The Christie, University of Manchester, Manchester, United Kingdom
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8
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Smith PS, West H, Whitworth J, Castle B, Sansbury FH, Warren AY, Woodward ER, Tischkowitz M, Maher ER. Pathogenic germline variants in patients with features of hereditary renal cell carcinoma: Evidence for further locus heterogeneity. Genes Chromosomes Cancer 2020; 60:5-16. [PMID: 32830346 DOI: 10.1002/gcc.22893] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/12/2020] [Accepted: 08/19/2020] [Indexed: 11/08/2022] Open
Abstract
Inherited renal cell carcinoma (RCC) is associated with multiple familial cancer syndromes but most individuals with features of non-syndromic inherited RCC do not harbor variants in the most commonly tested renal cancer predisposition genes (CPGs). We investigated whether undiagnosed cases might harbor mutations in CPGs that are not routinely tested for by testing 118 individuals with features suggestive of inherited RCC (family history of RCC, two or more primary RCC aged <60 years, or early onset RCC ≤46 years) for the presence of pathogenic variants in a large panel of CPGs. All individuals had been prescreened for pathogenic variants in the major RCC genes. We detected pathogenic or likely pathogenic (P/LP) variants of potential clinical relevance in 16.1% (19/118) of individuals, including P/LP variants in BRIP1 (n = 4), CHEK2 (n = 3), MITF (n = 1), and BRCA1 (n = 1). Though the power to detect rare variants was limited by sample size the frequency of truncating variants in BRIP1, 4/118, was significantly higher than in controls (P = 5.92E-03). These findings suggest that the application of genetic testing for larger inherited cancer gene panels in patients with indicators of a potential inherited RCC can increase the diagnostic yield for P/LP variants. However, the clinical utility of such a diagnostic strategy requires validation and further evaluation and in particular, confirmation of rarer RCC genotype-phenotype associations is required.
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Affiliation(s)
- Philip S Smith
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, and Cancer Research UK Cambridge Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Hannah West
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, and Cancer Research UK Cambridge Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - James Whitworth
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, and Cancer Research UK Cambridge Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Bruce Castle
- Peninsula Clinical Genetics Service, Royal Devon and Exeter NHS Foundation Trust, Royal Devon and Exeter Hospital (Heavitree), Exeter, UK University of Exeter Medical School, University of Exeter, Exeter, UK
| | - Francis H Sansbury
- Peninsula Clinical Genetics Service, Royal Devon and Exeter NHS Foundation Trust, Royal Devon and Exeter Hospital (Heavitree), Exeter, UK University of Exeter Medical School, University of Exeter, Exeter, UK.,All Wales Medical Genomics Service, Cardiff and Vale University Health Board, Institute of Medical Genetics, University Hospital of Wales, Cardiff, UK
| | - Anne Y Warren
- Department of Histopathology, Cambridge University NHS Foundation Trust and Cancer Research UK Cambridge Centre, Cambridge, UK
| | - Emma R Woodward
- Manchester Centre for Genomic Medicine and NW Laboratory Genetics Hub, Manchester University Hospitals NHS Foundation Trust, and Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Health Innovation Manchester, Manchester, UK
| | - Marc Tischkowitz
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, and Cancer Research UK Cambridge Centre, Cambridge Biomedical Campus, Cambridge, UK
| | - Eamonn R Maher
- Department of Medical Genetics, University of Cambridge and NIHR Cambridge Biomedical Research Centre, and Cancer Research UK Cambridge Centre, Cambridge Biomedical Campus, Cambridge, UK
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9
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Suszynska M, Ratajska M, Kozlowski P. BRIP1, RAD51C, and RAD51D mutations are associated with high susceptibility to ovarian cancer: mutation prevalence and precise risk estimates based on a pooled analysis of ~30,000 cases. J Ovarian Res 2020; 13:50. [PMID: 32359370 PMCID: PMC7196220 DOI: 10.1186/s13048-020-00654-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 04/24/2020] [Indexed: 12/24/2022] Open
Abstract
Background It is estimated that more than 20% of ovarian cancer cases are associated with a genetic predisposition that is only partially explained by germline mutations in the BRCA1 and BRCA2 genes. Recently, several pieces of evidence showed that mutations in three genes involved in the homologous recombination DNA repair pathway, i.e., BRIP1, RAD51C, and RAD51D, are associated with a high risk of ovarian cancer. To more precisely estimate the ovarian cancer risk attributed to BRIP1, RAD51C, and RAD51D mutations, we performed a meta-analysis based on a comparison of a total of ~ 29,400 ovarian cancer patients from 63 studies and a total of ~ 116,000 controls from the gnomAD database. Results The analysis allowed precise estimation of ovarian cancer risks attributed to mutations in BRIP1, RAD51C, and RAD51D, confirming that all three genes are ovarian cancer high-risk genes (odds ratio (OR) = 4.94, 95%CIs:4.07–6.00, p < 0.0001; OR = 5.59, 95%CIs:4.42–7.07, p < 0.0001; and OR = 6.94, 95%CIs:5.10–9.44, p < 0.0001, respectively). In the present report, we show, for the first time, a mutation-specific risk analysis associated with distinct, recurrent, mutations in the genes. Conclusions The meta-analysis provides evidence supporting the pathogenicity of BRIP1, RAD51C, and RAD51D mutations in relation to ovarian cancer. The level of ovarian cancer risk conferred by these mutations is relatively high, indicating that after BRCA1 and BRCA2, the BRIP1, RAD51C, and RAD51D genes are the most important ovarian cancer risk genes, cumulatively contributing to ~ 2% of ovarian cancer cases. The inclusion of the genes into routine diagnostic tests may influence both the prevention and the potential treatment of ovarian cancer.
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Affiliation(s)
- Malwina Suszynska
- Department of Molecular Genetics, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Street, 61-704, Poznan, Poland
| | - Magdalena Ratajska
- Department of Pathology, Dunedin School of Medicine, University of Otago, 60 Hanover Street, Dunedin, 9016, New Zealand.,Department of Biology and Medical Genetics, Medical University of Gdansk, Debinki 1 St., 80-210, Gdansk, Poland
| | - Piotr Kozlowski
- Department of Molecular Genetics, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Street, 61-704, Poznan, Poland.
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10
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Laner A, Benet-Pages A, Neitzel B, Holinski-Feder E. Analysis of 3297 individuals suggests that the pathogenic germline 5'-UTR variant BRCA1 c.-107A > T is not common in south-east Germany. Fam Cancer 2020; 19:211-213. [PMID: 32200540 DOI: 10.1007/s10689-020-00175-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 03/18/2020] [Indexed: 01/04/2023]
Abstract
In this study we aim to determine the prevalence of the recently identified pathogenic BRCA1 variant c.-107A > T in the south-east German population. This variant causes the epigenetic silencing of the BRCA1 promotor and has been detected in two independent families from the UK without a germline BRCA1 or BRCA2 pathogenic variant. A total of 3297 individuals with suspicion of hereditary breast and ovarian cancer and fulfilling the clinical criteria necessary for genetic testing in Germany were analyzed for presence of the variant by a Kompetitive Allele-Specific PCR (KASP) assay or direct Sanger sequencing. Since we did not detect an individual carrying the variant we conclude that BRCA1 c.-107A > T is not a common variant in the south-east German population.
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Affiliation(s)
- A Laner
- MGZ - Medizinisch Genetisches Zentrum, Bayerstr. 3-5, 80035, Munich, Germany.
| | - A Benet-Pages
- MGZ - Medizinisch Genetisches Zentrum, Bayerstr. 3-5, 80035, Munich, Germany.
| | - B Neitzel
- MGZ - Medizinisch Genetisches Zentrum, Bayerstr. 3-5, 80035, Munich, Germany
| | - E Holinski-Feder
- MGZ - Medizinisch Genetisches Zentrum, Bayerstr. 3-5, 80035, Munich, Germany.
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Terkelsen T, Christensen LL, Fenton DC, Jensen UB, Sunde L, Thomassen M, Skytte AB. Population frequencies of pathogenic alleles of BRCA1 and BRCA2: analysis of 173 Danish breast cancer pedigrees using the BOADICEA model. Fam Cancer 2020; 18:381-388. [PMID: 31435815 DOI: 10.1007/s10689-019-00141-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The Breast and Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA) calculates the probability that a woman carries a pathogenic variant in BRCA1 or BRCA2 based on her pedigree and the population frequencies of pathogenic alleles of BRCA1 (0.0006394) and BRCA2 (0.00102) in the United Kingdom (UK). BOADICEA allows the clinician to define the population frequencies of pathogenic alleles of BRCA1 and BRCA2 for other populations but only includes preset values for the Ashkenazy Jewish and Icelandic populations. Among 173 early-onset breast cancer pedigrees in Denmark, BOADICEA discriminated well between carriers and non-carriers of pathogenic variants (area under the receiver operating characteristics curve: 0.81; 95% CI 0.74-0.86) but underestimated the frequency of carriers of pathogenic variants in BRCA1 or BRCA2 as measured by the observed-to-expected ratio (O/E 1.83; 95% CI 1.18-2.84). This reflects findings from older studies of BOADICEA in UK, German, Italian, and Chinese populations, all accounting for the different calibration for different carrier probabilities. To improve the performance of BOADICEA for non-UK populations, we developed a method to derive population frequencies of pathogenic alleles of BRCA1 and BRCA2. Compared to the UK population frequencies, we estimated the Danish population frequencies of pathogenic alleles to be higher for BRCA1 (0.0015; 95% CI 0.00064-0.0034) and lower for BRCA2 (0.00052; 95% CI 0.00018-0.0017) after adjusting for the different calibration of BOADICEA for different carrier probabilities. Incorporating additional population frequencies into BOADICEA could improve its performance for non-UK populations.
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Affiliation(s)
- Thorkild Terkelsen
- Department of Clinical Genetics, Aarhus University Hospital, Brendstrupgaardsvej 21C, 8200, Aarhus N, Denmark.
| | | | | | - Uffe Birk Jensen
- Department of Clinical Genetics, Aarhus University Hospital, Brendstrupgaardsvej 21C, 8200, Aarhus N, Denmark
| | - Lone Sunde
- Department of Clinical Genetics, Aarhus University Hospital, Brendstrupgaardsvej 21C, 8200, Aarhus N, Denmark
| | - Mads Thomassen
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark
| | - Anne-Bine Skytte
- Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark
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12
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Zelli V, Compagnoni C, Cannita K, Capelli R, Capalbo C, Di Vito Nolfi M, Alesse E, Zazzeroni F, Tessitore A. Applications of Next Generation Sequencing to the Analysis of Familial Breast/Ovarian Cancer. High Throughput 2020; 9:ht9010001. [PMID: 31936873 PMCID: PMC7151204 DOI: 10.3390/ht9010001] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/02/2020] [Accepted: 01/07/2020] [Indexed: 12/24/2022] Open
Abstract
Next generation sequencing (NGS) provides a powerful tool in the field of medical genetics, allowing one to perform multi-gene analysis and to sequence entire exomes (WES), transcriptomes or genomes (WGS). The generated high-throughput data are particularly suitable for enhancing the understanding of the genetic bases of complex, multi-gene diseases, such as cancer. Among the various types of tumors, those with a familial predisposition are of great interest for the isolation of novel genes or gene variants, detectable at the germline level and involved in cancer pathogenesis. The identification of novel genetic factors would have great translational value, helping clinicians in defining risk and prevention strategies. In this regard, it is known that the majority of breast/ovarian cases with familial predisposition, lacking variants in the highly penetrant BRCA1 and BRCA2 genes (non-BRCA), remains unexplained, although several less penetrant genes (e.g., ATM, PALB2) have been identified. In this scenario, NGS technologies offer a powerful tool for the discovery of novel factors involved in familial breast/ovarian cancer. In this review, we summarize and discuss the state of the art applications of NGS gene panels, WES and WGS in the context of familial breast/ovarian cancer.
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Affiliation(s)
- Veronica Zelli
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, Via Vetoio, Coppito 2, 67100 L’Aquila, Italy; (V.Z.); (C.C.); (R.C.); (M.D.V.N.); (E.A.); (F.Z.)
- Center for Molecular Diagnostics and Advanced Therapies, University of L’Aquila, Via Petrini, 67100 L’Aquila, Italy
| | - Chiara Compagnoni
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, Via Vetoio, Coppito 2, 67100 L’Aquila, Italy; (V.Z.); (C.C.); (R.C.); (M.D.V.N.); (E.A.); (F.Z.)
| | - Katia Cannita
- Medical Oncology Unit, St Salvatore Hospital, Via L. Natali 1, 67100 L’Aquila, Italy;
| | - Roberta Capelli
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, Via Vetoio, Coppito 2, 67100 L’Aquila, Italy; (V.Z.); (C.C.); (R.C.); (M.D.V.N.); (E.A.); (F.Z.)
| | - Carlo Capalbo
- Department of Molecular Medicine, University of Rome “La Sapienza”, Viale Regina Elena 324, 00161 Rome, Italy;
| | - Mauro Di Vito Nolfi
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, Via Vetoio, Coppito 2, 67100 L’Aquila, Italy; (V.Z.); (C.C.); (R.C.); (M.D.V.N.); (E.A.); (F.Z.)
| | - Edoardo Alesse
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, Via Vetoio, Coppito 2, 67100 L’Aquila, Italy; (V.Z.); (C.C.); (R.C.); (M.D.V.N.); (E.A.); (F.Z.)
| | - Francesca Zazzeroni
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, Via Vetoio, Coppito 2, 67100 L’Aquila, Italy; (V.Z.); (C.C.); (R.C.); (M.D.V.N.); (E.A.); (F.Z.)
| | - Alessandra Tessitore
- Department of Biotechnological and Applied Clinical Sciences, University of L’Aquila, Via Vetoio, Coppito 2, 67100 L’Aquila, Italy; (V.Z.); (C.C.); (R.C.); (M.D.V.N.); (E.A.); (F.Z.)
- Center for Molecular Diagnostics and Advanced Therapies, University of L’Aquila, Via Petrini, 67100 L’Aquila, Italy
- Correspondence:
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13
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Montalban G, Bonache S, Moles-Fernández A, Gisbert-Beamud A, Tenés A, Bach V, Carrasco E, López-Fernández A, Stjepanovic N, Balmaña J, Diez O, Gutiérrez-Enríquez S. Screening of BRCA1/2 deep intronic regions by targeted gene sequencing identifies the first germline BRCA1 variant causing pseudoexon activation in a patient with breast/ovarian cancer. J Med Genet 2019; 56:63-74. [PMID: 30472649 DOI: 10.1136/jmedgenet-2018-105606] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 10/16/2018] [Accepted: 10/28/2018] [Indexed: 12/24/2022]
Abstract
BACKGROUND Genetic analysis of BRCA1 and BRCA2 for the diagnosis of hereditary breast and ovarian cancer (HBOC) is commonly restricted to coding regions and exon-intron boundaries. Although germline pathogenic variants in these regions explain about ~20% of HBOC cases, there is still an important fraction that remains undiagnosed. We have screened BRCA1/2 deep intronic regions to identify potential spliceogenic variants that could explain part of the missing HBOC susceptibility. METHODS We analysed BRCA1/2 deep intronic regions by targeted gene sequencing in 192 high-risk HBOC families testing negative for BRCA1/2 during conventional analysis. Rare variants (MAF <0.005) predicted to create/activate splice sites were selected for further characterisation in patient RNA. The splicing outcome was analysed by RT-PCR and Sanger sequencing, and allelic imbalance was also determined when heterozygous exonic loci were present. RESULTS A novel transcript was detected in BRCA1 c.4185+4105C>T variant carrier. This variant promotes the inclusion of a pseudoexon in mature mRNA, generating an aberrant transcript predicted to encode for a non-functional protein. Quantitative and allele-specific assays determined haploinsufficiency in the variant carrier, supporting a pathogenic effect for this variant. Genotyping of 1030 HBOC cases and 327 controls did not identify additional carriers in Spanish population. CONCLUSION Screening of BRCA1/2 intronic regions has identified the first BRCA1 deep intronic variant associated with HBOC by pseudoexon activation. Although the frequency of deleterious variants in these regions appears to be low, our study highlights the importance of studying non-coding regions and performing comprehensive RNA assays to complement genetic diagnosis.
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Affiliation(s)
- Gemma Montalban
- Oncogenetics Group, Vall d'Hebron Institut d'Oncologia, Barcelona, Spain
| | - Sandra Bonache
- Oncogenetics Group, Vall d'Hebron Institut d'Oncologia, Barcelona, Spain
| | | | | | - Anna Tenés
- Area of Clinical and Molecular Genetics, University Hospital of Vall d'Hebron, Barcelona, Spain
| | - Vanessa Bach
- Oncogenetics Group, Vall d'Hebron Institut d'Oncologia, Barcelona, Spain
| | - Estela Carrasco
- High Risk and Cancer Prevention Group, Vall d'Hebron Institut d'Oncologia, Barcelona, Spain
| | - Adrià López-Fernández
- High Risk and Cancer Prevention Group, Vall d'Hebron Institut d'Oncologia, Barcelona, Spain
| | - Neda Stjepanovic
- High Risk and Cancer Prevention Group, Vall d'Hebron Institut d'Oncologia, Barcelona, Spain
- Medical Oncology Department, University Hospital of Vall d'Hebron, Barcelona, Spain
| | - Judith Balmaña
- High Risk and Cancer Prevention Group, Vall d'Hebron Institut d'Oncologia, Barcelona, Spain
- Medical Oncology Department, University Hospital of Vall d'Hebron, Barcelona, Spain
| | - Orland Diez
- Oncogenetics Group, Vall d'Hebron Institut d'Oncologia, Barcelona, Spain
- Area of Clinical and Molecular Genetics, University Hospital of Vall d'Hebron, Barcelona, Spain
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14
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Morgan RD, Burghel GJ, Flaum N, Bulman M, Clamp AR, Hasan J, Mitchell CL, Schlecht H, Woodward ER, Lallo FI, Crosbie EJ, Edmondson RJ, Wallace AJ, Jayson GC, Evans DGR. Prevalence of germline pathogenic BRCA1/2 variants in sequential epithelial ovarian cancer cases. J Med Genet 2019; 56:301-307. [DOI: 10.1136/jmedgenet-2018-105792] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 12/14/2018] [Accepted: 01/05/2019] [Indexed: 12/29/2022]
Abstract
IntroductionPoly(ADP-ribose) polymerase inhibitors significantly improve progression-free survival in platinum-sensitive high-grade serous and endometrioid ovarian carcinoma, with greatest benefits observed in women with a pathogenic BRCA1/2 variant. Consequently, the demand for germline BRCA1/2 testing in ovarian cancer has increased substantially, leading to the screening of unselected populations of patients. We aimed to determine the prevalence of pathogenic germline BRCA1/2 variants in women diagnosed with epithelial ovarian cancer, categorised according to the established risk factors for hereditary breast and ovarian cancer syndrome and the Manchester BRCA Score, to inform risk stratification.MethodsA cohort of sequential epithelial ovarian cancer cases recruited between June 2013 and September 2018 underwent germline BRCA1/2 testing by next-generation sequencing and multiplex ligation-dependent probe amplification.ResultsFive hundred and fifty-seven patients were screened. Of these, 18% had inherited a pathogenic BRCA1/2 variant. The prevalence of pathogenic BRCA1/2 variants was >10% in women diagnosed with ovarian cancer earlier than 60 years of age (21%) and those diagnosed later than 60 years of age with a family history of breast and/or ovarian cancer (17%) or a medical history of breast cancer (34%). The prevalence of pathogenic BRCA1/2 variants was also >10% in women with a Manchester BRCA Score of ≥15 points (14%).DiscussionOur study suggests that age at diagnosis, family history of breast and/or ovarian cancer, medical history of breast cancer or a Manchester BRCA Score of ≥15 points are associated with a >10% prevalence of germline pathogenic BRCA1/2 variants in epithelial ovarian cancer.
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15
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Solodskikh SA, Panevina AV, Gryaznova MV, Gureev AP, Serzhantova OV, Mikhailov AA, Maslov AY, Popov VN. Targeted sequencing to discover germline variants in the BRCA1 and BRCA2 genes in a Russian population and their association with breast cancer risk. Mutat Res 2018; 813:51-57. [PMID: 30611917 DOI: 10.1016/j.mrfmmm.2018.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 12/27/2018] [Accepted: 12/28/2018] [Indexed: 02/08/2023]
Abstract
BRCA1 and BRCA2 are tumor suppressor genes involved in the repair of DNA damage and transcriptional regulation of the cell cycle. Alterations in BRCA1/2 lead to production of functionally defective proteins that impair DNA repair. Certain mutant variants of BRCA1/2 are strongly associated with increased risk of breast and ovarian cancers, with emerging data on association with other types of cancer. However, variability of BRCA1/2 in Russian populations remains understudied. In this study, we performed targeted sequencing of BRCA1/2 in 145 breast cancer (BC) patients with a family history of BRCA-associated cancers and 47 age-matched cancer-free control individuals with or without a family history of cancer. Subjects for this study were recruited in the Voronezh region of the Russian Federation. We found that two polymorphic variants, rs1799967 (BRCA1) and rs4987117 (BRCA2), were strongly associated with the risk of BC. Both variants have not been previously reported as associated with risk of breast cancer. Presence of the rs4987117 variant increases risk of breast cancer onset (OR = 2.76, p-value = 0.022). Notably, although variant rs80357906 (5382InsC) has been reported as a risk factor for hereditary BC, it was not significantly associated with breast cancer risk in our population (p = 0.192). We also found 12 novel polymorphic variants in BRCA1/2 genes (2 in BRCA1 and 10 in BRCA2). However, none of these variants demonstrated association with the disease. Five germline variants were observed at high frequency (mean AF = 67.14%) and therefore can be considered as a common haplotype in the Voronezh region of the Russian Federation. In summary, our study demonstrates that known pathological variants of BRCA1/2 genes may not be reflective of breast cancer risk assessment when applied to the Russian population. Further, more extended population-specific studies are needed to reveal the reliable list of BRCA1/2 polymorphisms associated with risk of breast cancer in the Russian population.
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Affiliation(s)
- Sergei A Solodskikh
- Department of Genetics, Cytology and Bioengineering, Voronezh State University, Voronezh, Russian Federation.
| | - Anna V Panevina
- Department of Genetics, Cytology and Bioengineering, Voronezh State University, Voronezh, Russian Federation; Department of Surgery, Voronezh Regional Clinical Oncological Dispensary, Voronezh, Russian Federation
| | - Maria V Gryaznova
- Department of Genetics, Cytology and Bioengineering, Voronezh State University, Voronezh, Russian Federation
| | - Artem P Gureev
- Department of Genetics, Cytology and Bioengineering, Voronezh State University, Voronezh, Russian Federation
| | - Olga V Serzhantova
- Department of Surgery, Voronezh Regional Clinical Oncological Dispensary, Voronezh, Russian Federation
| | - Andrei A Mikhailov
- Department of Surgery, Voronezh Regional Clinical Oncological Dispensary, Voronezh, Russian Federation
| | - Alexander Y Maslov
- Department of Genetics, Cytology and Bioengineering, Voronezh State University, Voronezh, Russian Federation; Department of Genetics, Albert Einstein College of Medicine of Yeshiva University, New-York, USA
| | - Vasily N Popov
- Department of Genetics, Cytology and Bioengineering, Voronezh State University, Voronezh, Russian Federation.
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16
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Evans DGR, van Veen EM, Byers HJ, Wallace AJ, Ellingford JM, Beaman G, Santoyo-Lopez J, Aitman TJ, Eccles DM, Lalloo FI, Smith MJ, Newman WG. A Dominantly Inherited 5' UTR Variant Causing Methylation-Associated Silencing of BRCA1 as a Cause of Breast and Ovarian Cancer. Am J Hum Genet 2018; 103:213-220. [PMID: 30075112 PMCID: PMC6080768 DOI: 10.1016/j.ajhg.2018.07.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 06/29/2018] [Indexed: 12/20/2022] Open
Abstract
Pathogenic variants in BRCA1 or BRCA2 are identified in ∼20% of families with multiple individuals affected by early-onset breast and/or ovarian cancer. Extensive searches for additional highly penetrant genes or alternative mutational mechanisms altering BRCA1 or BRCA2 have not explained the missing heritability. Here, we report a dominantly inherited 5' UTR variant associated with epigenetic BRCA1 silencing due to promoter hypermethylation in two families affected by breast and ovarian cancer. BRCA1 promoter methylation of ten CpG dinucleotides in families who are affected by breast and/or ovarian cancer but do not have germline BRCA1 or BRCA2 pathogenic variants was assessed by pyrosequencing and clonal bisulfite sequencing. RNA and DNA sequencing of BRCA1 from lymphocytes was undertaken to establish allelic expression and the presence of germline variants. BRCA1 promoter hypermethylation was identified in 2 of 49 families in which multiple women are affected by grade 3 breast cancer or high-grade serous ovarian cancer. Soma-wide BRCA1 promoter hypermethylation was confirmed in blood, buccal mucosa, and hair follicles. Pyrosequencing showed that DNA was ∼50% methylated, consistent with the silencing of one allele, which was confirmed by clonal bisulfite sequencing. RNA sequencing revealed the allelic loss of BRCA1 expression in both families and that this loss of expression segregated with the heterozygous variant c.-107A>T in the BRCA1 5' UTR. Our results establish a mechanism whereby familial breast and ovarian cancer is caused by an in cis 5' UTR variant associated with epigenetic silencing of the BRCA1 promoter in two independent families. We propose that methylation analyses be undertaken to establish the frequency of this mechanism in families affected by early-onset breast and/or ovarian cancer without a BRCA1 or BRCA2 pathogenic variant.
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Affiliation(s)
- D Gareth R Evans
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK; Prevention Breast Cancer Centre and Nightingale Breast Screening Centre, University Hospital of South Manchester, Manchester M23 9LT, UK; Christie NHS Foundation Trust, Manchester M20 4BX, UK; Manchester Breast Centre, Manchester Cancer Research Centre, University of Manchester, Manchester M20 4BX, UK.
| | - Elke M van Veen
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK; Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, UK
| | - Helen J Byers
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK; Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, UK
| | - Andrew J Wallace
- Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, UK
| | - Jamie M Ellingford
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK; Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, UK
| | - Glenda Beaman
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK; Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, UK
| | - Javier Santoyo-Lopez
- Centre for Genomic and Experimental Medicine and Edinburgh Genomics, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Timothy J Aitman
- Centre for Genomic and Experimental Medicine and Edinburgh Genomics, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Diana M Eccles
- Cancer Sciences Academic Unit and Southampton Clinical Trials Unit, Faculty of Medicine, University of Southampton and University Hospital Southampton Foundation Trust, Southampton S016 6YD, UK
| | - Fiona I Lalloo
- Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, UK
| | - Miriam J Smith
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK; Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, UK
| | - William G Newman
- Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine, and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester M13 9PL, UK; Manchester Breast Centre, Manchester Cancer Research Centre, University of Manchester, Manchester M20 4BX, UK; Manchester Centre for Genomic Medicine, St. Mary's Hospital, Manchester University NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester M13 9WL, UK.
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17
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Evans DG, Howell SJ, Howell A. Personalized prevention in high risk individuals: Managing hormones and beyond. Breast 2018; 39:139-147. [PMID: 29610032 DOI: 10.1016/j.breast.2018.03.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 03/17/2018] [Accepted: 03/24/2018] [Indexed: 12/01/2022] Open
Abstract
Increasing numbers of women are being identified at 'high-risk' of breast cancer, defined by The National Institute of Health and Care Excellence (NICE) as a 10-year risk of ≥8%. Classically women have been so identified through family history based risk algorithms or genetic testing of high-risk genes. Recent research has shown that assessment of mammographic density and single nucleotide polymorphisms (SNPs), when combined with established risk factors, trebles the number of women reaching the high risk threshold. The options for risk reduction in such women include endocrine chemoprevention with the selective estrogen receptor modulators tamoxifen and raloxifene or the aromatase inhibitors anastrozole or exemestane. NICE recommends offering anastrozole to postmenopausal women at high-risk of breast cancer as cost effectiveness analysis showed this to be cost saving to the National Health Service. Overall uptake to chemoprevention has been disappointingly low but this may improve with the improved efficacy of aromatase inhibitors, particularly the lack of toxicity to the endometrium and thrombogenic risks. Novel approaches to chemoprevention under investigation include lower dose and topical tamoxifen, denosumab, anti-progestins and metformin. Although oophorectomy is usually only recommended to women at increased risk of ovarian cancer it has been shown in numerous studies to reduce breast cancer risks in the general population and in those with mutations in BRCA1/2. However, recent evidence from studies that have confined analysis to true prospective follow up have cast doubt on the efficacy of oophorectomy to reduce breast cancer risk in BRCA1 mutation carriers, at least in the short-term.
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Affiliation(s)
- D Gareth Evans
- Manchester Centre for Genomic Medicine, Division of Evolution and Genomic Sciences, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Science Centre, Manchester, UK; Prevent Breast Cancer and Nightingale Breast Screening Centre, Wythenshawe Hospital Manchester Universities Foundation Trust, Manchester, UK; Manchester Academic Health Science Centre, University of Manchester, Manchester, UK; The Christie NHS Foundation Trust, Manchester, UK; Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK; Manchester Breast Centre, Manchester Cancer Research Centre, University of Manchester, Manchester, UK.
| | - Sacha J Howell
- Prevent Breast Cancer and Nightingale Breast Screening Centre, Wythenshawe Hospital Manchester Universities Foundation Trust, Manchester, UK; Manchester Academic Health Science Centre, University of Manchester, Manchester, UK; The Christie NHS Foundation Trust, Manchester, UK; Manchester Breast Centre, Manchester Cancer Research Centre, University of Manchester, Manchester, UK
| | - Anthony Howell
- Prevent Breast Cancer and Nightingale Breast Screening Centre, Wythenshawe Hospital Manchester Universities Foundation Trust, Manchester, UK; Manchester Academic Health Science Centre, University of Manchester, Manchester, UK; The Christie NHS Foundation Trust, Manchester, UK; Manchester Breast Centre, Manchester Cancer Research Centre, University of Manchester, Manchester, UK
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18
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Schayek H, Korach H, Laitman Y, Bernstein-Molho R, Friedman E. Mutational analysis of candidate genes in Israeli male breast cancer cases. Breast Cancer Res Treat 2018; 170:399-404. [PMID: 29560538 DOI: 10.1007/s10549-018-4765-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 03/17/2018] [Indexed: 12/18/2022]
Abstract
PURPOSE To define the mutational spectrum of several candidate gene mutations in Israeli male breast cancer cases. METHODS MBC cases counselled at the Oncogenetics unit, Sheba Medical Center from January 1998 to June 2017 were included. Relevant clinical and oncological data and cancer phenotype were retrieved. All participants were genotyped for the predominant Jewish BRCA1 and BRCA2 germline mutations using a chip-based assay. Those who tested negative were further genotyped for three recurring mutations in CHEK2 (c.1100delC, p.S428F, p.I157T), and single mutations in the FANCM (c.5791C>T), and RAD51D (c.556C>T) genes, by direct sequencing. The ethics committee approved the study. RESULTS Overall, 61 MBC were identified and genotyped, 41 (67.2%) were Ashkenazim, age at diagnosis was 58.1 ± 12.6 years, and 31 (50.8%) had a family history of cancer. Of genotyped individuals, one (1.6%) harboured the 185delAG* BRCA1 mutation, 7 (11.4%) the 6174delT*BRCA2 mutation and 2 (3.2%) other recurring mutations in BRCA2 (overall 10/61-16.4% BRCA1/BRCA2 mutation carriers). Of BRCA-negative cases, 3/51 (5.9%) carried the p.S428F *CHEK2 mutation. None was a carrier of the other genotyped mutations in CHEK2, FANCM or RAD51D. CONCLUSION BRCA1, BRCA2 and CHEK2 germline mutations contribute to inherited predisposition to MBC in Israel.
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Affiliation(s)
- Hagit Schayek
- The Susanne Levy Gertner Oncogenetics Unit, Institute of Human Genetics, Sheba Medical Center, Tel-Hahsomer, Israel
| | - Hila Korach
- The Susanne Levy Gertner Oncogenetics Unit, Institute of Human Genetics, Sheba Medical Center, Tel-Hahsomer, Israel.,The Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Yael Laitman
- The Susanne Levy Gertner Oncogenetics Unit, Institute of Human Genetics, Sheba Medical Center, Tel-Hahsomer, Israel
| | - Rinat Bernstein-Molho
- The Breast Cancer Unit, Oncology Institute, Sheba Medical Center, Tel-Hashomer, Israel.,The Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Eitan Friedman
- The Susanne Levy Gertner Oncogenetics Unit, Institute of Human Genetics, Sheba Medical Center, Tel-Hahsomer, Israel. .,The Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel. .,The Danek Gertner Institute of Human Genetics, Chaim Sheba Medical Center, 52621, Tel-Hashomer, Israel.
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19
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Chatterjee M, Sheela M, Mukherjee U, Patil S, Satheesh C, Murugan K, Naik R, Rao N, Mahesh B, Mannan UA, Gupta V, Sankaran S, Ajaikumar B, Ghosh M. Incidental Findings in Male Breast Carcinoma: A Genetic Counseling Approach. INT J HUM GENET 2017. [DOI: 10.1080/09723757.2016.11886287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Manjima Chatterjee
- Triesta Sciences, HCG, Bangalore, Karnataka, India
- School of Bio Sciences and Technology, VIT University, Vellore 632 014, Tamil Nadu, India
| | - M.L. Sheela
- Triesta Sciences, HCG, Bangalore, Karnataka, India
| | - Upasana Mukherjee
- Triesta Sciences, HCG, Bangalore, Karnataka, India
- School of Bio Sciences and Technology, VIT University, Vellore 632 014, Tamil Nadu, India
| | - Shekar Patil
- Health Care Global Enterprises Limited, Bangalore 560 027, Karnataka, India
| | - C.T. Satheesh
- Health Care Global Enterprises Limited, Bangalore 560 027, Karnataka, India
| | - Krithika Murugan
- Health Care Global Enterprises Limited, Bangalore 560 027, Karnataka, India
| | - Radheshyam Naik
- Health Care Global Enterprises Limited, Bangalore 560 027, Karnataka, India
| | - Nalini Rao
- Health Care Global Enterprises Limited, Bangalore 560 027, Karnataka, India
| | - B. Mahesh
- Health Care Global Enterprises Limited, Bangalore 560 027, Karnataka, India
| | - U. Ashraf Mannan
- Strand Centre for Genomics and Personalized Medicine, Bangalore 560 024, Karnataka, India
| | - Vaijayanti Gupta
- Strand Centre for Genomics and Personalized Medicine, Bangalore 560 024, Karnataka, India
| | - Satish Sankaran
- Strand Centre for Genomics and Personalized Medicine, Bangalore 560 024, Karnataka, India
| | - B.S. Ajaikumar
- Health Care Global Enterprises Limited, Bangalore 560 027, Karnataka, India
| | - Mithua Ghosh
- Triesta Sciences, HCG, Bangalore, Karnataka, India
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20
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Bubien V, Bonnet F, Dupiot-Chiron J, Barouk-Simonet E, Jones N, de Reynies A, MacGrogan G, Sevenet N, Letouzé E, Longy M. Combined tumor genomic profiling and exome sequencing in a breast cancer family implicates ATM in tumorigenesis: A proof of principle study. Genes Chromosomes Cancer 2017; 56:788-799. [PMID: 28691344 DOI: 10.1002/gcc.22482] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Revised: 05/11/2017] [Accepted: 07/06/2017] [Indexed: 11/08/2022] Open
Abstract
Familial breast cancers (BCs) account for 10%-20% of all diagnosed BCs, yet only 20% of such tumors arise in the context of a germline mutation in known tumor suppressor genes such as BRCA1 or BRCA2. The vast genetic heterogeneity which characterizes non BRCA1 and non BRCA2 (or BRCAx) families makes grouped studies impossible to perform. Next generation sequencing techniques, however, allow individual families to be studied to identify rare and or private mutations but the high number of genetic variants identified need to be sorted using pathogenicity or recurrence criteria. An additional sorting criterion may be represented by the identification of candidate regions defined by tumor genomic rearrangements. Indeed, comparative genomic hybridization (CGH) using single nucleotide polymorphism (SNP) arrays allows the detection of conserved ancestral haplotypes within recurrent regions of loss of heterozygosity, common to several familial tumors, which can highlight genomic loci harboring a germline mutation in cancer predisposition genes. The combination of both exome sequencing and SNP array-CGH for a series of familial BC revealed a germline ATM mutation associated with a loss of the wild-type allele in two BC from a BRCAx family. The analysis of additional breast tumors from ten BC families in which a germline ATM mutation had been identified revealed a high frequency of wild-type allele loss. This result argues strongly in favor of the involvement of ATM in these tumors as a tumor suppressor gene and confirms that germline ATM mutations are involved in a subset of familial BC.
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Affiliation(s)
- Virginie Bubien
- INSERM U1218, Mammary & Leukemic Oncogenesis group, Université de Bordeaux, Bordeaux, France.,Cancer Genetics Department, Institut Bergonié, Bordeaux, France
| | - Françoise Bonnet
- INSERM U1218, Mammary & Leukemic Oncogenesis group, Université de Bordeaux, Bordeaux, France.,Cancer Genetics Department, Institut Bergonié, Bordeaux, France
| | | | | | - Natalie Jones
- INSERM U1218, Mammary & Leukemic Oncogenesis group, Université de Bordeaux, Bordeaux, France.,Cancer Genetics Department, Institut Bergonié, Bordeaux, France
| | - Aurélien de Reynies
- Programme CIT, Bioinformatics Department, Ligue Nationale contre le Cancer (Cartes d'Identité des Tumeurs), Paris, France
| | - Gaëtan MacGrogan
- INSERM U1218, Mammary & Leukemic Oncogenesis group, Université de Bordeaux, Bordeaux, France.,BioPathology Department, Institut Bergonié, Bordeaux, France
| | - Nicolas Sevenet
- INSERM U1218, Mammary & Leukemic Oncogenesis group, Université de Bordeaux, Bordeaux, France.,Cancer Genetics Department, Institut Bergonié, Bordeaux, France
| | - Eric Letouzé
- Programme CIT, Bioinformatics Department, Ligue Nationale contre le Cancer (Cartes d'Identité des Tumeurs), Paris, France
| | - Michel Longy
- INSERM U1218, Mammary & Leukemic Oncogenesis group, Université de Bordeaux, Bordeaux, France.,Cancer Genetics Department, Institut Bergonié, Bordeaux, France
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21
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Evans DG, Harkness EF, Plaskocinska I, Wallace AJ, Clancy T, Woodward ER, Howell TA, Tischkowitz M, Lalloo F. Pathology update to the Manchester Scoring System based on testing in over 4000 families. J Med Genet 2017; 54:674-681. [PMID: 28490612 DOI: 10.1136/jmedgenet-2017-104584] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 04/03/2017] [Accepted: 04/09/2017] [Indexed: 11/03/2022]
Abstract
BACKGROUND While the requirement for thresholds for testing for mutations in BRCA1/2 is being questioned, they are likely to remain for individuals unaffected by a relevant cancer. It is still useful to provide pretesting likelihoods, but models need to take into account tumour pathology. METHODS The Manchester Scoring System (MSS) is a well-used, simple, paper-based model for assessing carrier probability that already incorporates pathology data. We have used mutation testing data from 4115 unrelated samples from affected non-Jewish individuals alongside tumour pathology to further refine the scoring system. RESULTS Adding additional points for high-grade serous ovarian cancer <60 (HGSOC=+2) and adding grade score to those with triple-negative breast cancer, while reducing the score for those with HER2+ breast cancer (-6), resulted in significantly improved sensitivity and minor improvements in specificity to the MSS. Sporadic HGSOC <60 years thus reached a score of 15-19 points within the 10% grouping consistent with the 15/113-13.2% that were identified with a BRCA1/2 pathogenic variant. Validation in a population series of ovarian cancer from Cambridge showed high sensitivity at the 10% threshold 15/17 (88.2%). CONCLUSIONS The new pathology-adjusted Manchester score MSS3 appears to provide an effective and simple-to-use estimate of the 10% and 20% thresholds for BRCA1/2 likelihood. For unaffected individuals, the 20-point (20%) threshold in their affected first-degree relative can be used to determine eligibility at the 10% threshold.
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Affiliation(s)
- D Gareth Evans
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester Academic Health Centre, Division of Evolution and Genomic Medicine, University of Manchester, Manchester, UK.,Prevent Breast Cancer Prevention Centre, University Hospital of South Manchester NHS Foundation Trust, Wythenshawe, Manchester, UK.,Manchester Centre for Genomic Medicine, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK.,Manchester Breast Centre, The Christie, Manchester, UK.,Department of Medical Oncology, The Christie, Manchester, UK
| | - Elaine F Harkness
- Division of Informatics, Imaging and Data Sciences, University of Manchester, Manchester, UK
| | - Inga Plaskocinska
- Department of Medical Genetics and National Institute for Health Research Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, UK
| | - Andrew J Wallace
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Tara Clancy
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Emma R Woodward
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester Academic Health Centre, Division of Evolution and Genomic Medicine, University of Manchester, Manchester, UK.,Manchester Centre for Genomic Medicine, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Tony A Howell
- Prevent Breast Cancer Prevention Centre, University Hospital of South Manchester NHS Foundation Trust, Wythenshawe, Manchester, UK.,Department of Medical Oncology, The Christie, Manchester, UK
| | - Marc Tischkowitz
- Department of Medical Genetics and National Institute for Health Research Cambridge Biomedical Research Centre, University of Cambridge, Cambridge, UK
| | - Fiona Lalloo
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
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22
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Functional classification of DNA variants by hybrid minigenes: Identification of 30 spliceogenic variants of BRCA2 exons 17 and 18. PLoS Genet 2017; 13:e1006691. [PMID: 28339459 PMCID: PMC5384790 DOI: 10.1371/journal.pgen.1006691] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 04/07/2017] [Accepted: 03/14/2017] [Indexed: 11/30/2022] Open
Abstract
Mutation screening of the breast cancer genes BRCA1 and BRCA2 identifies a large fraction of variants of uncertain clinical significance (VUS) whose functional and clinical interpretations pose a challenge for genomic medicine. Likewise, an increasing amount of evidence indicates that genetic variants can have deleterious effects on pre-mRNA splicing. Our goal was to investigate the impact on splicing of a set of reported variants of BRCA2 exons 17 and 18 to assess their role in hereditary breast cancer and to identify critical regulatory elements that may constitute hotspots for spliceogenic variants. A splicing reporter minigene with BRCA2 exons 14 to-20 (MGBR2_ex14-20) was constructed in the pSAD vector. Fifty-two candidate variants were selected with splicing prediction programs, introduced in MGBR2_ex14-20 by site-directed mutagenesis and assayed in triplicate in MCF-7 cells. Wild type MGBR2_ex14-20 produced a stable transcript of the expected size (1,806 nucleotides) and structure (V1-[BRCA2_exons_14–20]–V2). Functional mapping by microdeletions revealed essential sequences for exon recognition on the 3’ end of exon 17 (c.7944-7973) and the 5’ end of exon 18 (c.7979-7988, c.7999-8013). Thirty out of the 52 selected variants induced anomalous splicing in minigene assays with >16 different aberrant transcripts, where exon skipping was the most common event. A wide range of splicing motifs were affected including the canonical splice sites (15 variants), novel alternative sites (3 variants), the polypyrimidine tract (3 variants) and enhancers/silencers (9 variants). According to the guidelines of the American College of Medical Genetics and Genomics (ACMG), 20 variants could be classified as pathogenic (c.7806-2A>G, c.7806-1G>A, c.7806-1G>T, c.7806-1_7806-2dup, c.7976+1G>A, c.7977-3_7978del, c.7977-2A>T, c.7977-1G>T, c.7977-1G>C, c.8009C>A, c.8331+1G>T and c.8331+2T>C) or likely pathogenic (c.7806-9T>G, c.7976G>C, c.7976G>A, c.7977-7C>G, c.7985C>G, c.8023A>G, c.8035G>T and c.8331G>A), accounting for 30.8% of all pathogenic/likely pathogenic variants of exons 17–18 at the BRCA Share database. The remaining 8 variants (c.7975A>G, c.7977-6T>G, c.7988A>T, c.7992T>A, c.8007A>G, c.8009C>T, c.8009C>G, and c.8072C>T) induced partial splicing anomalies with important ratios of the full-length transcript (≥70%), so that they remained classified as VUS. Aberrant splicing is therefore especially prevalent in BRCA2 exons 17 and 18 due to the presence of active ESEs involved in exon recognition. Splicing functional assays with minigenes are a valuable strategy for the initial characterization of the splicing outcomes and the subsequent clinical interpretation of variants of any disease-gene, although these results should be checked, whenever possible, against patient RNA. A significant proportion of disease-causing mutations of inherited disorders impair splicing. Massive sequencing projects of genetic diseases generate thousands of sequence variations that require functional and clinical interpretations. We have shown that splicing reporter minigenes of the breast cancer genes BRCA1 and BRCA2 are useful tools to functionally test DNA variants. In this work, we have constructed a 7-exon BRCA2 minigene (exons 14 to 20) where we mapped critical splicing regulatory sequences and tested 52 selected variants of exons 17 and 18 detected in breast cancer patients. We finely located three DNA segments on both exons that presumably contain splicing enhancer sequences. We observed that a total of 30 variants of any type disrupted the splicing patterns and, given the severity of their outcomes, we classified 20 of them as pathogenic or likely pathogenic. We also showed that a wide range of splicing elements were affected including canonical and novel 5’ and 3’ splice sites, the polypyrimidine tract and enhancer and silencer sequences. We concluded that splicing aberrations are frequent in Hereditary Breast and Ovarian Cancer and that minigenes are valuable tools to functionally classify DNA variants of any human disease gene under the splicing viewpoint.
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23
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Evans DG, Brentnall A, Byers H, Harkness E, Stavrinos P, Howell A, Newman WG, Cuzick J. The impact of a panel of 18 SNPs on breast cancer risk in women attending a UK familial screening clinic: a case-control study. J Med Genet 2017; 54:111-113. [PMID: 27794048 DOI: 10.1136/jmedgenet-2016-104125] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Revised: 09/01/2016] [Accepted: 10/07/2016] [Indexed: 01/06/2023]
Abstract
BACKGROUND Breast cancer familial risk clinics offer screening and preventive strategies. While BRCA1/BRCA2 genetic testing provides important risk information for some women, panels of more common breast cancer risk genetic variants may have relevance to greater numbers of women with familial risk. METHODS Three polygenic risk scores (PRS) based on 18 SNPs were investigated in a case-control study of women attending a familial risk clinic. PRS were derived from published general European population allele ORs and frequencies (18-SNPs (SNP18)). In women with BRCA1/BRCA2 mutations, 3 SNPs/13 SNPs, respectively, generated the PRS estimates. In total, 364 incident breast cancer cases (112 with BRCA1/2 mutations) were matched with 1605 controls (691 BRCA1/2) by age last mammogram and BRCA1/2 genetic test result. 87 women with cancer before attendance were also considered. Logistic regression was used to measure PRS performance through ORs per IQR and calibration of the observed to expected (O/E) logarithm relative risk when unadjusted and adjusted for phenotypic risk factors assessed by the Tyrer-Cuzick (TC) model. RESULTS SNP18 was predictive for non-carriers of BRCA1/2 mutations (IQR OR 1.55, 95% CI 1.29 to 1.87, O/E 96%). Findings were unaffected by adjustment from TC (IQR OR 1.56, 95% CI 1.29 to 1.89) or when prior cancers were included (IQR OR 1.55, 95% CI 1.30 to 1.87). There was some evidence to support polygenic scores with weights for individuals with BRCA1/2 mutations (BRCA1 IQR OR 1.44, 95% CI 1.17 to 1.76; BRCA2 IQ OR 1.44, 95% CI 0.90 to 2.31). CONCLUSIONS PRS may be used to refine risk assessment for women at increased familial risk who test negative/have low likelihood of BRCA1/2 mutations. They may alter the recommended prevention strategy for many women attending family history clinics.
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Affiliation(s)
- D Gareth Evans
- Genesis Breast Cancer Prevention Centre and Nightingale Breast Screening Centre, University Hospital of South Manchester, Manchester, UK
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
- Central Manchester Foundation Trust, Manchester, UK
| | - Adam Brentnall
- Centre for Cancer Prevention, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK
| | - Helen Byers
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
- Central Manchester Foundation Trust, Manchester, UK
| | - Elaine Harkness
- Centre for Imaging Sciences, Institute for Population Health, University of Manchester, Manchester, UK
| | - Paula Stavrinos
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
- Central Manchester Foundation Trust, Manchester, UK
| | - Anthony Howell
- Genesis Breast Cancer Prevention Centre and Nightingale Breast Screening Centre, University Hospital of South Manchester, Manchester, UK
- The Christie NHS Foundation Trust, Manchester, UK
| | - William G Newman
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
- Central Manchester Foundation Trust, Manchester, UK
| | - Jack Cuzick
- Centre for Cancer Prevention, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK
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