Smaller HR estimates in BRCA1 breast cancer were seen for the PRS for overall breast cancer (HR = 1.14, 95% CI = 1.11 to 1.17, P = 1.8×10−18) and ER-positive breast cancer (HR = 1.11, 95% CI =  1.08 to 1.15, P = 3.5×10−13). This evidence concerns the gene BRCA1 and breast carcinoma.