Estrogen metabolite found to suppress tumour growth, but how?

Abstract

2-methoxyestradiol, a minor metabolite of estrogen, has turned out to be a major inhibitor of cell proliferation. Groups on either side of the Atlantic agree that it could have significant antitumour effects, but they have different ideas about how it should be exploited as a therapeutic agent. European researchers think of it as an angiogenesis inhibitor, while US researchers dispute such a specific inhibitory effect against blood vessel growth and plan to take it forward as a nonspecific inhibitor of cell division.