The search for the ideal SERM.

Selective oestrogen receptor modulators (SERMs) are compounds that interact with the oestrogen receptor and have tissue-specific effects distinct from those of oestradiol, acting as an oestrogen agonist in some tissues and as an antagonist in others. The development of SERMs that selectively interact with specific receptors, coactivators and corepressors in different organ systems offers the possibility of improving the risk:benefit profile relative to hormone replacement therapy. Tamoxifen is a SERM that acts as an oestrogen antagonist in breast tissue and is currently being used for the treatment and prevention of breast cancer. Tamoxifen also exhibits oestrogen-agonistic properties in the endometrium and increases the risk of endometrial cancer. Oestrogen and another SERM, raloxifene, have been shown to prevent osteoporosis. The effects of oestrogens on cognitive functions are currently being investigated. Recent data reveal the lack of secondary prevention of coronary heart disease with oestrogen. Oestrogen has been used to treat menopausal symptoms, whereas the SERMs have been shown to induce hot flushes. Current research is focused on producing the ideal SERM, which would have benefits over existing SERMs in terms of preventing cancer, cardiovascular disease, osteoporosis and menopausal symptoms, improving cognitive functions, and have a significantly better toxicity profile in terms of endometrial cancer and thromboembolic events.