A functional BRCA1 coding sequence genetic variant contributes to prognosis of triple-negative breast cancer, especially after radiotherapy

As a subtype of breast cancer, triple-negative breast cancer (TNBC) shows poor prognosis and high heterogeneity. Precise identification of TNBC subgroups relevant to clinical prognosis is crucial in the design and administration of individualized treatments. This study aimed to evaluate the prognostic value of the functional BRCA1 rs799917 genetic variant in TNBC. Associations between the rs799917 polymorphism and progression risk were investigated after genotyping 370 TNBC patients. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated by Cox regression. We found that the rs799917T allele was associated with a significantly increased risk of disease progression and shortened progression-free survival time (PFS) (P = 0.001 for log-rank test). Notably, TNBC patients with the rs799917 CC genotype showed about 22 months prolonged PFS compared to the TT genotype after radiotherapy (HR 4.44, 95% CI 1.98-9.93; P = 2.9 x 10(-4)). Additionally, in overweight patients, the mean PFS of the rs799917TT genotype was 10 months shorter than that of the CC genotype (HR 3.57, 95% CI 1.46-8.73, P = 0.005). Our findings demonstrate that the functional BRCA1 genetic variant contributes to prognosis of TNBC. Our study also highlights the clinical potential of this polymorphism in the screening of high-risk TNBC patients for recurrence and the possibility of patient-tailored decisions especially during radiotherapy.