CYP17A1 and neoplasm: Patients expressing constitutively active AR-Vs will in the long-term probably not benefit from anti-androgen therapies aiming to reduce steroid synthesis, such as surgical castration, LHRH analogs, or the newly introduced agent abiraterone that inhibits CYP17 and thereby steroid synthesis not only in testis but also in the adrenal glands and in tumor tissue [19], [20].