4-Methoxyestradiol

**Semantic type:** Organic Chemical|Pharmacologic Substance

**Definition:** An endogenous metabolite formed during the O-methylation of the highly carcinogenic catechol estrogen 4-hydroxyestradiol (4-OHE2) by catechol-O-methyltransferase (COMT), with potential anti-proliferative activity. Even though the exact mechanism of action through which 4-methoxyestradiol (4-MeE2) exerts its effect is not fully elucidated, this chemical appears to have antiproliferative and apoptosis-inducing activities in susceptible tumor cells.

**Synonyms:** - 4-MeE2 - 4-MeOE2 - 4-Methoxyestradiol-17 Beta - 4-Methoxyestradiol-17beta - Estra-1,3,5(10)-Triene-3,17-Diol, 4-Methoxy-, (17beta)-