The novel estrogen receptor - GPER - in estrogen sensitive malignancies

Estrogen effects are mediated either through genomic action involving the classical estrogen receptors, estrogen receptor alpha and beta, which function as transcription fac- tors in the nucleus, or through rapid non-genomic action via receptors associated with membranes in the cell. Recently, a member of the G protein-coupled receptor family was ascri- bed estrogen receptor properties, thus a candidate for me- diating non-genomic estrogen signaling. G protein-coupled estrogen receptor, GPER, has high affinity for estrogen and signals via various mitogenic pathways. interestingly, selective estrogen receptor modulators, such as tamoxifen and iCi 182 780 act as GPER agonists. Current studies analyzed GPER mRNA and protein in estrogen sensitive gynecological malignancies, such as endometrial, ovarian, and breast cancer and related the expression to diagnosis or prognosis. Real-time reverse transcription-polymerase chain reaction, Western Blot, immune histochemistry, immune transmission electron microscopy, and confocal microscopy were employed to map GPER expression, tissue distribution, and subcellular localization. GPER, predomi- nantly localized in epithelial cells, was expressed in all tissues studied. However, inconsistent results have been obtained regarding the relation to histopathlogical parameters or clinical outcome. These discrepancies and possible clinical implication will be discussed in the subsequent presentation.