BRCA1 and breast cancer: The risk of breast cancer in the first-degree relatives of BRCA1 and BRCA2 probands was significantly higher than in first-degree relatives of non-carrier families (hazard ratio, HR=3.31, 95% CI 2.46-4.44, p<0.001; HR=3.31, 95% CI 2.46-4.44, p<0.001 for BRCA1 and BRCA2 respectively).