BRCA2 and breast cancer: All these results appeared to be similar in BRCA1 and BRCA2. Nevertheless, our results suggest a variation in BC risk associated with parity according to the location of the mutation in BRCA1. Indeed, parity seems to be associated with a significantly decreased risk of BC only among women with a mutation in the central region of BRCA1 (low-risk region) (≥1 versus 0 FTP: HR = 0.27, 95% CI = 0.13 to 0.55) (Pinteraction <10-3).