CTLA4 and cancer: Ipilimumab (Yervoy®) developed by Medarex (Princeton, NJ, USA), is a fully humanized monoclonal antibody that binds to the ECD of CTLA-4, specifically blocks the interaction between CTLA-4 and B7-1 or B7-2, and eventually maintains T-cell cytotoxicity to attack cancer cells [164,165].