ABSTRACT
Prostate cancer (PC) is the second-most frequently diagnosed cancer in men worldwide, with 1.1 million new cases estimated to have occurred in 2012. Systematic treatment for advanced or metastatic PC includes androgen deprivation therapy (ADT) or chemotherapy. Conventional ADT involved surgical or medical castration and the administration of anti-androgen agents, such as bicalutamide, flutamide, and nilutamide. New anti-androgen agents, such as enzalutamide and abiraterone, have been approved for castration-resistant (CR) PC. Docetaxel and cabazitaxel are also available for CRPC. However, effects of the agents are transitory. Estrogens actions on prostatic epithelium have been considered to be exerted via ERa-mediated paracrine mechanism. Conversely, the exposure of humans or rodents to estrogens induced proliferative changes and squamous metaplasia in their prostates. Noble strain rats treated with androgen plus estrogens over a long period have been reported to show high PC incidence.
