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Girardi F, Barnes DR, Barrowdale D, Frost D, Brady AF, Miller C, Henderson A, Donaldson A, Murray A, Brewer C, Pottinger C, Evans DG, Eccles D, Lalloo F, Gregory H, Cook J, Eason J, Adlard J, Barwell J, Ong KR, Walker L, Izatt L, Side LE, Kennedy MJ, Tischkowitz M, Rogers MT, Porteous ME, Morrison PJ, Eeles R, Davidson R, Snape K, Easton DF, Antoniou AC. Risks of breast or ovarian cancer in BRCA1 or BRCA2 predictive test negatives: findings from the EMBRACE study. Genet Med 2018; 20:1575-1582. [PMID: 29565421 PMCID: PMC6033314 DOI: 10.1038/gim.2018.44] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 01/12/2018] [Indexed: 12/30/2022] Open
Abstract
PURPOSE BRCA1/BRCA2 predictive test negatives are proven noncarriers of a BRCA1/BRCA2 mutation that is carried by their relatives. The risk of developing breast cancer (BC) or epithelial ovarian cancer (EOC) in these women is uncertain. The study aimed to estimate risks of invasive BC and EOC in a large cohort of BRCA1/BRCA2 predictive test negatives. METHODS We used cohort analysis to estimate incidences, cumulative risks, and standardized incidence ratios (SIRs). RESULTS A total of 1,895 unaffected women were eligible for inclusion in the BC risk analysis and 1,736 in the EOC risk analysis. There were 23 incident invasive BCs and 2 EOCs. The cumulative risk of invasive BC was 9.4% (95% confidence interval (CI) 5.9-15%) by age 85 years and the corresponding risk of EOC was 0.6% (95% CI 0.2-2.6%). The SIR for invasive BC was 0.93 (95% CI 0.62-1.40) in the overall cohort, 0.85 (95% CI 0.48-1.50) in noncarriers from BRCA1 families, and 1.03 (95% CI 0.57-1.87) in noncarriers from BRCA2 families. The SIR for EOC was 0.79 (95% CI 0.20-3.17) in the overall cohort. CONCLUSION Our results did not provide evidence for elevated risks of invasive BC or EOC in BRCA1/BRCA2 predictive test negatives.
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Affiliation(s)
- Fabio Girardi
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Daniel R Barnes
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Daniel Barrowdale
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Debra Frost
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Angela F Brady
- North West Thames Regional Genetics Service, Northwick Park Hospital, London North West Healthcare NHS Trust, Harrow, UK
| | - Claire Miller
- Cheshire and Merseyside Clinical Genetics Service, Liverpool Women's NHS Foundation Trust, Liverpool, UK
| | - Alex Henderson
- Institute of Genetic Medicine, Centre for Life, Newcastle Upon Tyne Hospitals NHS Trust, Newcastle upon Tyne, UK
| | - Alan Donaldson
- Clinical Genetics Department, St Michael's Hospital, Bristol, UK
| | - Alex Murray
- All Wales Medical Genetics Services, Singleton Hospital, Swansea, UK
| | - Carole Brewer
- Department of Clinical Genetics, Royal Devon & Exeter Hospital, Exeter, UK
| | | | - D Gareth Evans
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, Division of Evolution and Genomic Science, Manchester University, Manchester Universities NHS Foundation Trust, Manchester, UK
| | - Diana Eccles
- University of Southampton Faculty of Medicine, Southampton University Hospitals NHS Trust, Southampton, UK
| | - Fiona Lalloo
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, Manchester Universities NHS Foundation Trust, Manchester, UK
| | - Helen Gregory
- North of Scotland Regional Genetics Service, NHS Grampian & University of Aberdeen, Foresterhill, Aberdeen, UK
| | - Jackie Cook
- Sheffield Clinical Genetics Service, Sheffield Children's Hospital, Sheffield, UK
| | - Jacqueline Eason
- Nottingham Clinical Genetics Service, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Julian Adlard
- Yorkshire Regional Genetics Service, Chapel Allerton Hospital, Leeds, UK
| | - Julian Barwell
- Leicestershire Clinical Genetics Service, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Kai Ren Ong
- West Midlands Regional Genetics Service, Birmingham Women's Hospital Healthcare NHS Trust, Birmingham, UK
| | - Lisa Walker
- Oxford Regional Genetics Service, Churchill Hospital, Oxford, UK
| | - Louise Izatt
- Clinical Genetics, Guy's and St. Thomas' NHS Foundation Trust, London, UK
| | - Lucy E Side
- North East Thames Regional Genetics Service, Great Ormond Street Hospital for Children NHS Trust, London, UK
| | - M John Kennedy
- Academic Unit of Clinical and Molecular Oncology, Trinity College Dublin and St James's Hospital, Dublin, Ireland
| | - Marc Tischkowitz
- Department of Medical Genetics, University of Cambridge, Cambridge, UK
| | - Mark T Rogers
- All Wales Medical Genetics Services, University Hospital of Wales, Cardiff, UK
| | - Mary E Porteous
- South East of Scotland Regional Genetics Service, Western General Hospital, Edinburgh, UK
| | - Patrick J Morrison
- Centre for Cancer Research and Cell Biology, Queens University of Belfast, Belfast, UK
| | - Ros Eeles
- Oncogenetics Team, The Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London, UK
| | - Rosemarie Davidson
- Department of Clinical Genetics, South Glasgow University Hospitals, Glasgow, UK
| | - Katie Snape
- Medical Genetics Unit, St George's, University of London, London, UK
| | - Douglas F Easton
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
- Centre for Cancer Genetic Epidemiology, Department of Oncology, University of Cambridge, Cambridge, UK
| | - Antonis C Antoniou
- Centre for Cancer Genetic Epidemiology, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.
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Revertant mosaicism for family mutations is not observed in BRCA1/2 phenocopies. PLoS One 2017; 12:e0171663. [PMID: 28199346 PMCID: PMC5310879 DOI: 10.1371/journal.pone.0171663] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 01/24/2017] [Indexed: 11/19/2022] Open
Abstract
In BRCA1/2 families, early-onset breast cancer (BrCa) cases may be also observed among non-carrier relatives. These women are considered phenocopies and raise difficult counselling issues concerning the selection of the index case and the residual risks estimate in negative family members. Few studies investigated the presence of potential genetic susceptibility factors in phenocopies, mainly focussing on BrCa-associated single-nucleotide polymorphisms. We hypothesized that, as for other Mendelian diseases, a revertant somatic mosaicism, resulting from spontaneous correction of a pathogenic mutation, might occur also in BRCA pedigrees. A putative low-level mosaicism in phenocopies, which has never been investigated, might be the causal factor undetected by standard diagnostic testing. We selected 16 non-carriers BrCa-affected from 15 BRCA1/2 families, and investigated the presence of mosaicism through MALDI-TOF mass spectrometry. The analyses were performed on available tumour samples (7 cases), blood leukocytes, buccal mucosa and urine samples (2 cases) or on blood only (7 cases). In one family (n.8), real-time PCR was also performed to analyse the phenocopy and her healthy parents. On the 16 phenocopies we did not detect the family mutations neither in the tumour, expected to display the highest mutation frequency, nor in the other analysed tissues. In family 8, all the genotyping assays did not detect mosaicism in the phenocopy or her healthy parents, supporting the hypothesis of a de novo occurrence of the BRCA2 mutation identified in the proband. These results suggest that somatic mosaicism is not likely to be a common phenomenon in BRCA1/2 families. As our families fulfilled high-risk selection criteria, other genetic factors might be responsible for most of these cases and have a significant impact on risk assessment in BRCA1/2 families. Finally, we found a de novo BRCA2 mutation, suggesting that, although rare, this event should be taken into account in the evaluation of high-risk families.
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Baert A, Depuydt J, Van Maerken T, Poppe B, Malfait F, Van Damme T, De Nobele S, Perletti G, De Leeneer K, Claes KBM, Vral A. Analysis of chromosomal radiosensitivity of healthy BRCA2 mutation carriers and non-carriers in BRCA families with the G2 micronucleus assay. Oncol Rep 2017; 37:1379-1386. [PMID: 28184943 PMCID: PMC5364849 DOI: 10.3892/or.2017.5407] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 10/03/2016] [Indexed: 01/07/2023] Open
Abstract
Breast cancer risk drastically increases in individuals with a heterozygous germline BRCA1 or BRCA2 mutation, while it is estimated to equal the population risk for relatives without the familial mutation (non-carriers). The aim of the present study was to use a G2 phase-specific micronucleus assay to investigate whether lymphocytes of healthy BRCA2 mutation carriers are characterized by increased radiosensitivity compared to controls without a family history of breast/ovarian cancer and how this relates to healthy non-carrier relatives. BRCA2 is active in homologous recombination, a DNA damage repair pathway, specifically active in the late S/G2 phase of the cell cycle. We found a significantly increased radiosensitivity in a cohort of healthy BRCA2 mutation carriers compared to individuals without a familial history of breast cancer (P=0.046; Mann-Whitney U test). At the individual level, 50% of healthy BRCA2 mutation carriers showed a radiosensitive phenotype (radiosensitivity score of 1 or 2), whereas 83% of the controls showed no radiosensitivity (P=0.038; one-tailed Fishers exact test). An odds ratio of 5 (95% CI, 1.07–23.47) indicated an association between the BRCA2 mutation and radiosensitivity in healthy mutation carriers. These results indicate the need for the gentle use of ionizing radiation for either diagnostic or therapeutic use in BRCA2 mutation carriers. We detected no increased radiosensitivity in the non-carrier relatives.
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Affiliation(s)
- Annelot Baert
- Department of Basic Medical Sciences, Ghent University, B-9000 Ghent, Belgium
| | - Julie Depuydt
- Department of Basic Medical Sciences, Ghent University, B-9000 Ghent, Belgium
| | - Tom Van Maerken
- Department of Pediatrics and Medical Genetics, Ghent University, B-9000 Ghent, Belgium
| | - Bruce Poppe
- Center for Medical Genetics, Ghent University Hospital, B-9000 Ghent, Belgium
| | - Fransiska Malfait
- Center for Medical Genetics, Ghent University Hospital, B-9000 Ghent, Belgium
| | - Tim Van Damme
- Center for Medical Genetics, Ghent University Hospital, B-9000 Ghent, Belgium
| | - Sylvia De Nobele
- Center for Medical Genetics, Ghent University Hospital, B-9000 Ghent, Belgium
| | - Gianpaolo Perletti
- Department of Basic Medical Sciences, Ghent University, B-9000 Ghent, Belgium
| | - Kim De Leeneer
- Center for Medical Genetics, Ghent University Hospital, B-9000 Ghent, Belgium
| | - Kathleen B M Claes
- Center for Medical Genetics, Ghent University Hospital, B-9000 Ghent, Belgium
| | - Anne Vral
- Department of Basic Medical Sciences, Ghent University, B-9000 Ghent, Belgium
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