Based on the 45 290 European-ancestry breast cancer cases and 41 880 controls from the BCAC iCOGS study, none of the 171 CYP19A1 locus SNPs with P<10−4 for endometrial cancer were associated with breast cancer (Michailidou et al. 2013) (minimum P=0.0033, data not shown). Here, CYP19A1 is linked to breast cancer.