Methods and kits for characterizing a subject having a steroid-dependent disease such as prostate cancer are described. A method of treating a steroid-dependent disease in a subject by obtaining a biological sample from the subject, determining if the HSD3B1(1245C) gene or 3βHSD1(367T) protein is expressed in the biological sample, and providing treatment other than or in addition to steroid ablation to the subject if the HSD3B1(1245C) gene or 3βHSD1(367T) protein is expressed is also described.