- A substance that keeps androgens (male sex hormones) from binding to proteins called androgen receptors, which are found in normal prostate cells, some prostate cancer cells, and in cells of some other tissues. Preventing this binding blocks the effects of these hormones in the body. Treatment with antiandrogens may keep prostate cancer cells from growing. Examples of antiandrogens used to treat prostate cancer are apalutamide, bicalutamide, enzalutamide, flutamide, and nilutamide. Also called androgen receptor antagonist and androgen receptor blocker.