Hormonal agents are used to treat some cancers. An example is:

Estrogen antagonists are commonly used to treat estrogen hormone-dependent cancers such as breast carcinoma. One well-known estrogen antagonist used in breast cancer therapy is Tamoxifen (Nolvadex). This drug, in combination with surgery and other chemotherapeutic drugs, reduces breast cancer recurrence by 30%. Estrogen antagonists can also be administered to prevent breast cancer in women who have a strong family history. Thyroxine is a thyroid hormone used to treat hypothyroidism, not thyroid cancer. ACTH is an anterior pituitary hormone that stimulates the adrenal glands to release glucocorticoids; it does not treat adrenal cancer. Glucagon is a pancreatic alpha cell hormone that stimulates glycogenolysis and gluconeogenesis; it does not treat pancreatic cancer.