Rather than stimulating T cells, however, CTLA-4 provides inhibitory signals to the T cell, serving as a negative feedback loop.[2–4] Theoretically, blocking CTLA-4 using McAbs (monoclonal antibody) may sustain the activation and proliferation of tumor-specific T cells, so it can initiate the development of an effective tumor-specific immune response. This evidence concerns the gene CTLA4 and neoplasm.