Sipuleucel-T (Provenge) is a "vaccine" for advanced prostate cancer that helps prolong survival. Provenge isn't your everyday vaccine. It's an immune therapy created by harvesting immune cells from a patient, genetically engineering them to fight prostate cancer, and then infusing them back into the patient. It's approved only for treatment of patients with few or no prostate cancer symptoms whose cancer has spread outside the prostate gland and is no longer responding to hormone therapy.