Estrogens play essential roles in the progression of mammary and prostatic diseases. The
transcriptional effects of estrogens are transduced by two estrogen receptors, ERa and ERb,
which elicit opposing roles in regulating proliferation: ERa is proliferative while ERb is anti-
proliferative. Exogenous expression of ERb in ERa-positive cancer cell lines inhibits cell
proliferation in response to estrogen and reduces xenografted tumor growth in vivo,
suggesting that ERb might oppose ERa's proliferative effects via formation of ERa/b …

Estrogens play essential roles in the progression of mammary and prostatic diseases. The
transcriptional effects of estrogens are transduced by two estrogen receptors, ERα and ERβ,
which elicit opposing roles in regulating proliferation: ERα is proliferative while ERβ is anti-
proliferative. Exogenous expression of ERβ in ERα-positive cancer cell lines inhibits cell
proliferation in response to estrogen and reduces xenografted tumor growth in vivo,
suggesting that ERβ might oppose ERα's proliferative effects via formation of ERα/β …