BRCA1 and breast cancer: For ovarian cancers, although the HRs were of similar magnitude as for breast cancers in BRCA1 and BRCA2 carriers, respectively, the HRs were not significant (BRCA2 carriers, P = 0.10 and BRCA1 carriers, P = 0.11) likely reflecting the smaller number of events (Table 1 and Table S1).