CTLA4 and cancer: As demonstrated by the accumulated evidence, application of monoclonal antibodies against the two best characterized ICs, the cytotoxic T-lymphocyte antigen-4 (CTLA-4) and the programmed death-1 (PD-1) receptor, constitutes a major breakthrough in experimental and clinical oncology and demonstrates the potential of immune-mediated therapies in achieving durable cancer remissions [13,16,20,21,22,23].