Estrogens have been recently postulated as potential agents in the development and progression of prostate
cancer. Previous studies have demonstrated presence of both variants of estrogen receptor (ER); ER alpha (ERα) and ER
beta (ERβ) in differing proportions between normal prostate and prostate cancer. It has been previously suggested that
estrogens may either accelerate or inhibit growth of prostate cancer cell growth, depending on ER status. In particular,
ERβ is considered to have a growth inhibitory role in prostate tissue. ERβ is significantly expressed in human prostate
cancer cells, and hence it is considered a key factor for anti-cancer therapy. Therefore, various types of ERβ ligands have
been investigated to clarify the mechanism of ERβ-mediated pathway of inhibitory effects on prostate cancer cells.
Herein, we review recent examinations of ERs in prostate cancer, and the significance of ER mediated signaling
pathways, with a focus on ERβ, as prospective therapeutic targets in prostate cancer.