BRCA1 and breast cancer: Further analysis, adjusting by age at diagnosis, showed that BRCA1 and BRCA2 carriers had a significant worse prognosis than individuals of the other groups (Fig. 4a), with HR of 3.2 (95% CI = 1.5 to 6.7; p = 0.002) and 2.6 (95%CI = 1.5 to 4.7; p = 0.001) respectively, when compared with BC of sporadic origin.