In addition, estrogen may promote the proliferation of hormone-dependent tumor cells through the following mechanisms: (1) regulate the expression of early genes related to cell division, such as c-myc, c-jun and c-fos, and promote DNA synthesis and division; Stimulate the expression of growth factors, such as epidermal growth factor (EGF), insulin-like growth factor I II (IGF-II) and transforming growth factor-A (TGF-a) to promote cell proliferation; (3) Regulate the expression of regulatory proteins related to cell cycle, such as cyclin-B2, and affect cell proliferation. This evidence concerns the gene MYC and neoplasm.