Phase III clinical trials have shown that ipilimumab, a human IgG1 monoclonal antibody that blocks CTLA-4, significantly prolongs progression-free survival (PFS) and overall survival (OS) in patients with advanced melanoma when compared to gp100 vaccination [2] or dacarbazine (DTIC) [3], with an overall response rate (ORR) of 11%, a median PFS of 2.9 months (mo), and a median OS of 10.1 mo. The gene discussed is CTLA4; the disease is melanoma.