Estrogen receptors--known and unknown biological functions.

The present literature review includes the data available from 1995 to 2005 about the biological functions of estrogen receptors (ERs) and their role in tumorigenesis. The domain organisation,and cell and tissue localization of two estrogen receptors are described. The article reviews the well known function of these receptors as transcription factors and their less familiar extracellular "non-genome" effects. Because of their stimulating effect on cell proliferation estrogens are supposed to actively participate in the genesis and development of some malignant conditions. We draw particular attention to the significance these estrogen receptors have for the onset and development of tumors outside the reproductive system. Knowledge of the receptor mechanisms of estrogenic action may enhance the diagnostic and therapeutic opportunities to treat a wide range of neoplastic lesions.