Aromatase (AR) (also known as estrogen synthase) is a complex enzyme of microsomal cytochrome P450, which consists of hemoglobin P450a rom and reduced coenzyme NADPH, which are widely found in ovary, liver, muscle, In fat and breast cancer cells, it is a key enzyme and rate-limiting enzyme that catalyzes the conversion of androgens to estrogen in the body. It can aromatize the androgen ring A, remove the 19-position carbon atom and convert the 1-position carbonyl group into a hydroxyl group. This will catalyze the conversion of androgens such as androstenedione and testosterone to estrone and estradiol, the latter being the main source of estrogen in postmenopausal women. Estrogen is involved in tumor progression, and aromatase plays a final rate-limiting catalytic role in estrogen biosynthesis.
Aromatase inhibitors (AI) can specifically cause aromatase inactivation, block aromatization, inhibit estrogen production, and lower estrogen levels in the blood to achieve breast cancer treatment. Mostly used in postmenopausal women with advanced breast cancer who have failed anti-estrogen (tamoxifen) treatment. Commonly used aromatase inhibitors: exemestane, letrozole, anastrozole.