Aromatase Inhibitors: A Safer Approach for the Treatment of Breast Cancer

Breast cancer is the second leading cause of cancer death in women. About two-thirds of breast cancers are termed hormone-dependent breast cancer, which contains estrogen receptors (ER) and requires estrogen for tumor growth. Aromatase, the enzyme involved in the last step of the biosynthesis of estrogens from androgens, are potential targets for the prevention and treatment of this type of breast cancer. Aromatase inhibitors can markedly suppress plasma estrogen levels by inhibiting aromatase. However, these compounds inhibit aromatase activity in a global fashion and thus could adversely impact sites where estrogen is required for normal function. This drawback has encouraged researchers to develop new drugs that can selectively inhibit aromatase for breast cancer.