[2-Methoxyestradiol -- a new compound for cancer treatment].

2-Methoxyestradiol (2-ME2), a physiological metabolite of estrogen, inhibits the growth of different tumor types. Many mechanisms of action have been described. In addition to a strong antiangiogenic effect and induction of apoptosis, there are other important mechanisms, such as the inhibition of microtubules during mitosis or the inhibition of the hypoxia-inducible-factor 1alpha (HIF1 alpha). Multidrug-resistant cancer cells appear to be highly sensitive to 2-ME2. Studies with high dosage 2-ME2 have shown that there are only minimal reversible side effects on normal tissue. The experimental data on human tumors have led to the initiation of several clinical trials with promising results. We here summarize the effect of 2-ME2 on various tumor types in vitro and in vivo, as well as the initial results of current clinical trials.