Purpose: Pathogenic/likely pathogenic (P/LP) germline variations in BRCA1 and BRCA2 genes are responsible for the majority of hereditary breast and ovarian cancers. This study presents the BRCA1/BRCA2 sequencing and deletion duplication analyses results of of 493 participants (485 women, 8 men) selected based on the National Comprehensive Cancer Network (NCCN) guidelines.
Methods: Next generation sequencing (NGS) and multiplex ligation-dependent probe amplification methods (MLPA) were used to define germline BRCA1/BRCA2 positivity.
Results: Overall, the P/LP frequency of the participants was 17.8%. Five of the likely pathogenic variants were novel. The 5266dupC pathogenic variation, which is a founder mutation in the Ashkenazi Jewish population, was the most common variation among the patients, with a frequency of 5.47%. The pathogenic/likely pathogenic variation frequency was significantly higher (p=0.01) among clinically diagnosed familial cancer patisents than those participants without personal history of cancer but enrolled for BRCA1 testing due to familial risk. BRCA1/BRCA mutation positivity was significantly higher (p=0.000) among those who had at least one first- or second-degree relative with breast/ovarian cancer from patients who had no family history. BRCA1/BRCA2 mutation positivity was 69.23% between the patients who had personal history of both breast and ovarian cancer.
Conclusion: Based on our findings, we suggest that sequencing all of the coding regions of the BRCA1/BRCA2 genes using NGS is a feasible approach for individuals who are at risk of developing BRCA-related cancer according to NCCN guidelines. The 5266dupC pathogenic variation, as the most common pathogenic variation in the Trakya region of Turkey, should be included if a targeted mutatin screening is planned.