Prevalence of BRCA1 and BRCA2 pathogenic variants in a large, unselected breast cancer cohort.
Wen, Wei Xiong
Christensen, Helene Nordahl
International journal of cancer
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Li, J., Wen, W. X., Eklund, M., Kvist, A., Eriksson, M., Christensen, H. N., Torstensson, A., et al. (2019). Prevalence of BRCA1 and BRCA2 pathogenic variants in a large, unselected breast cancer cohort.. International journal of cancer, 144 (5), 1195-1204. https://doi.org/10.1002/ijc.31841
Breast cancer patients with BRCA1/2-driven tumors may benefit from targeted therapy. It is not clear whether current BRCA screening guidelines are effective at identifying these patients. The purpose of this study was to evaluate the prevalence of inherited BRCA1/2 pathogenic variants in a large, clinically representative breast cancer cohort and to estimate the proportion of BRCA1/2 carriers not detected by selectively screening individuals with the highest probability of being carriers according to current clinical guidelines. The study included 5,122 unselected Swedish breast cancer patients diagnosed from 2001 to 2008. Target sequence enrichment (48.48 Fluidigm Access Arrays) and sequencing were performed (Illumina Hi-Seq 2500 instrument, v4 chemistry). Differences in patient and tumor characteristics of BRCA1/2 carriers who were already identified as part of clinical BRCA1/2 testing routines and additional BRCA1/2 carriers found by sequencing the entire study population were compared using logistic regression models. Ninety-two of 5,099 patients with valid variant calls were identified as BRCA1/2 carriers by screening all study participants (1.8%). Only 416 study participants (8.2%) were screened as part of clinical practice, but this identified 35 out of 92 carriers (38.0%). Clinically-identified carriers were younger, less likely postmenopausal and more likely to be associated with familiar ovarian cancer compared to the additional carriers identified by screening all patients. More BRCA2 (34/42, 81.0%) than BRCA1 carriers (23/50, 46%) were missed by clinical screening. In conclusion, BRCA1/2 mutation prevalence in unselected breast cancer patients was 1.8%. Six in ten BRCA carriers were not detected by selective clinical screening of individuals.
Humans, Breast Neoplasms, Ovarian Neoplasms, Genetic Predisposition to Disease, BRCA1 Protein, BRCA2 Protein, Prevalence, Cohort Studies, Mutation, Middle Aged, Female
Cancer Research UK (16563)
Cancer Research UK (16565)
Cancer Research UK (CRUK-A16563)
Wellcome Trust (203477/Z/16/Z)
External DOI: https://doi.org/10.1002/ijc.31841
This record's URL: https://www.repository.cam.ac.uk/handle/1810/283081