Function of estrogen receptor (ER) in gene expression.

Estrogen (E2) plays significant roles in ligand target organs such as the reproductive organs, bone and the brain. This female steroid hormone is well known also to be deeply involved in cancer development in the reproductive organs. The majority of E2 actions are mediated through its nuclear estrogen receptor (ER). ERa and ER~ are members of the steroid/thyroid hormone nuclear receptor superfamily, and they act as ligand-inducible transcription factors to control expression of a particular set of target genes for E2. In cancer development, growth factors are shown to act synergistically with E2, possibly modulating the function of ER. In this review, the molecular mechanism of this cross-talk is discussed.