Parl FF, et al. - Researchers investigated the causal relationship of estrogens to tumor formation in breast cancers. The genesis of this malignancy was noted to be driven by 82 genes with 916 point mutations discovered in a recent study of 560 breast cancers. In view of the major role estrogens have in breast cancer development and in the regulation of the expression of numerous genes, researchers investigated if estrogens, such as 17β-estradiol (E2), and the estrogen receptor, ESR1 (ERα) influence the 82 driver genes. In this analysis, mutations in estrogen-regulated genes showed more frequent association with elevated breast cancer risk, while mutations in unregulated genes showed more frequent association with acute myeloid leukemia.