Aromatase in health and disease

Aromatase is a key enzyme for estrogen formation in human tissues. Although ovarian aromatase expression is shut down after the menopause, age-related increases in aromatase expression in peripheral tissues (adipose and skin) modify the severity of estrogen deficiency by elevating plasma estradiol. In fact, circulating estradiol may persist at sufficient levels to cause postmenopausal uterine bleeding, endometrial hyperplasia, and even cancer. Local expression of aromatase in other tissues (brain and bone) may also have physiologically significant consequences, such as maintenance of cognitive function and bone mass. Finally, clinical relevance of estrogen formation via aberrant aromatase expression in breast cancer and postmenopausal endometriosis has been exemplified by the successful treatment of these estrogen-dependent conditions using aromatase inhibitors [62,63].