One key finding we showed in this study is that overexpression of ERRα could confer in vitro resistance to androgen-deprivation and in vivo castration-resistant growth capacity in AR-positive prostate cancer cells via a mechanism of direct transactivation of some key androgen synthetic enzyme genes, leading to enhanced intracellular de novo androgen production in prostate cancer cells. The gene discussed is ESRRA; the disease is prostate cancer.