Eric Small, MD, and colleagues from the UCSF Comprehensive Cancer Center, are investigating a new vaccine designed to battle an especially serious form of prostate cancer.  The vaccine has shown promising results in early clinical trials, and may help men with advanced prostate cancer live longer. UCSF scientists say patients who received the vaccine, called Provenge, live longer than men who are on a placebo. Unlike traditional vaccine, Provenge does not prevent the disease; rather, it triggers the immune system to fight the cancer after it has already developed.