Raloxifene: another selective estrogen modulator.

The role of estrogens as one of the prime stimulators of tumor cell proliferation is well recognized; efforts to interfere with the initiation and promotion of breast and other cancers by endocrine manipulation have a long and successful past. The benzothiophene derivate Raloxifene is a relatively recent newcomer into a heterogeneous family of compounds loosely called antiestrogens, which implies their ability to act as antagonists to estrogen effects via competitive binding to various steroid receptors. This is a reductionist explanation, since their action is colorful and varied; they interact with lipid transduction cascades, covalently bind to DNA and to different proteins and regulate growth factors and the expression of various genes, such as erB2, mdr1 and p53; they complex with E-cadherin/catenin and are thus able to induce apoptosis, actively or indirectly. Raloxifene not only modulates estrogen effects, but has been found to reduce bone demineralization and atherogenesis, without carcinogenic stimulation of the endometrium.