of a tumor-promoting hormone called insulin-like growth factor-1 (IGF1).[27][unreliable medical source?] * Anabolic steroids such as testosterone, fluoxymesterone, drostanolone propionate, epitiostanol, and mepitiostane have historically been used to treat breast cancer because of their antiestrogenic effects in the breasts but are now rarely if ever used due to their virilizing side effects.[28]Route/form