A hormone is an internally secreted compound, such as insulin or thyroxine, formed in endocrine glands. Hormones affect the functions of specifically receptive organs or tissues when transported to them by the body fluids. Pharmaceutically, a hormone is a synthetic substance used in medicine to act like a compound when introduced into the body.
Hormones help regulate body mechanisms such as growth, metabolism, and reproduction.
Hormones can be used to alter the growth of cancer. Cancer therapy, which achieves its anti-tumor effect through changes in hormonal balance, is also called endocrine therapy. Some tissues, such as prostate or breast, depend on hormones to develop. When a malignancy arises in these tissues, it is usually hormone responsive. Other primaries and histologic types may be hormone responsive, such as melanoma and hypernephroma. Hormonal therapy may effect a long-term control of the cancer growth.
Prednisone is a common hormone that is administered to cancer patients, especially in combination with multi-agent chemotherapy regimens.
An anti-hormone is an agent that works against a hormone or a hormone's response in the body. Many anti-hormone agents have been developed to interfere with the interaction between the hormone molecule and its receptor site, which stimulates cell growth and proliferation.
Tamoxifen (also called Nolvadex) is the first anti-estrogen to achieve widespread clinical use. It has become standard first-line anti-hormonal therapy for metastatic breast cancer and for adjuvant therapy of early stage breast cancer in postmenopausal women. Tamoxifen acts by attaching to the cell surface estrogen receptor without initiating the intracellular processes which leads to proliferation. Its presence at the receptor site blocks the attachment estrogen and thus interferes with their actions on breast cells and breast cancer cells.
Anti-androgens such as Flutamide are used as anti-hormone treatment in the medical management of advanced prostate cancer. Flutamide attaches to androgen receptors on prostate cancer cells and blocks the actions of testosterone and dihydrotestosterone in stimulating cell growth.