Description
Estrogen receptor-beta, referred to as ESR2 or ERb, is a member of the superfamily of nuclear receptors which can transduce extracellular signals into transcriptional responses. This gene is mapped to 14q and comprises 8 exons spanning approximately 40 kb. It is expressed in multiple tissues, including developing spermatids of the testis and in ovarian granulosa cells. ERb is homologous to the previously identified ERa and has an overlapping but nonidentical tissue distribution. The DNA-binding domain of ERb is 96% conserved compared to ERa, and the ligand-binding domain shows 58% conserved residues. Estrogen receptor beta is expressed in human thymus, spleen, ovary, and testis. ERb mRNA was coexpressed with ERa and its splice variants in 60% of prolactinomas, 100% of mixed growth hormone /prolactin tumors, and 29% of gonadotroph tumors. Gene expression was not limited to ERa-positive tumor subtypes, however, and was also found in 100% of null cell tumors, 80% of somatotroph tumors, and 60% of corticotroph tumors