While there were no significant differences in the associations with ER-positive and ER-negative disease among BRCA1 carriers (PHet=0.12), the associations were stronger for ER-negative (rs115635831 HR=1.32, P=3 × 10−3) than ER-positive breast cancer (rs115635831 overall HR=1.21, P=0.018) using the retrospective likelihood model (Supplementary Table 12). This evidence concerns the gene BRCA1 and breast carcinoma.