BRCA1 and breast cancer: Log HR estimates for overall breast cancer risk in BRCA2 carriers were very similar to the log odds ratios (ORs) from the general population (ICC = 0.63, 95% CI: 0.47 to 0.75) (Additional file 1: Figure S3B), whereas there was only moderate correlation between the log HR estimates for BRCA1 carriers and the log HR estimates from both other groups (ICC: BRCA1-BCAC estimates = 0.43, BRCA1-BRCA2 = 0.46) (Additional file 1: Figure S3A,C).