The link between estrogen signaling, PKIB, and castration-resistant prostate cancer is further indicated by the study by Chung et al. Chung’s study demonstrated that the induced overexpression of PKIB in prostate cancer increased the aggressiveness of the cancer cells, whereas the knockdown of PKIB decreased the cancer cells’ aggressiveness [36]. The gene discussed is PKIB; the disease is Familial prostate cancer.