Prostate cancer is the second-leading cause of cancer-related death among men and the seventh most common cause of death in the United States overall. Most prostate cancers are androgen-dependent, meaning that they respond to androgen-ablation therapy. However, these tumors eventually become androgen-independent and grow despite androgen ablation. When prostate cancer is localized in the prostate, the treatment of choice is prostatectomy or irradiation. However, when the tumor relapses or is already metastatic at diagnosis, therapy is problematic. Androgen ablation has been the main option for unconfined disease for more than 50 years, since Clarence V. Hodges and Charles B. Huggins . . .