Prostate cancer (PCa) is the most common male malignancy in many Western countries. Primary PCa is hormone dependent and is manageable by hormonal therapy. However, it rapidly develops to hormone-refractory tumors due to the accumulation of mutations in the androgen receptor and/or the acquisition of alternative cellular pathways that support proliferation and inhibit apoptosis of prostate cancer. To date, no effective therapy is available for clinically hormone-insensitive or hormone-refractory stages of prostate cancer.