Aromatase in endometriosis and uterine leiomyomata

Abstract Endometrial tissue from uterine disease-free women does not exhibit aromatase activity. In contrast, aromatase enzyme activity and mRNA levels are readily detectable in endometriosis. PGE 2 stimulates both aromatase expression and activity in endometriotic stromal cells via promoter II region of the aromatase gene. This results in local production of estradiol, which induces PGE 2 formation and establishes a positive feedback cycle. This mechanism seems to contribute to continuous production of estradiol and PGE 2 . Aromatase mRNA levels and enzyme activity are also present in uterine leiomyomata that are estrogen-dependent benign tumors of the myometrium. Successful treatment of endometriosis and uterine leiomyomata using aromatase inhibitors by recent pilot trials underscores the clinical significance of these molecular studies.