In the analyses based on data from the genetic consortia, genetic predisposition to higher serum E2 levels proxied by rs727479 in the CYP19A1 gene was associated with increased risk of ER-positive breast cancer (OR 1.02; 95% CI, 1.01-1.03; P = 2.5 × 10−3) as well as with endometrial cancer overall (OR 1.09; 95% CI, 1.06-1.11; P = 7.3 × 10−13) and the endometrioid histology subtype (OR 1.10; 95% CI, 1.07-1.13; P = 2.1 × 10−11) (Fig. 1). This evidence concerns the gene CYP19A1 and endometrial cancer.