CYP19A1 and endometrial cancer: Although E2 concentrations and endometrial cancer risks are both higher in women with larger BMI regardless of CYP19A1 genotype, there also appears to be a gene-environment interaction such that the associations of the rs727479 A allele with E2 concentration and also with endometrial cancer risk increase according to BMI, with BMI presumably serving as a proxy for the amount of adipose tissue (Fig. 1).