CTLA4 and neoplasm: Immunotherapies such as high-dose interleukin-2 (IL-2), adoptive T cell transfer (ACT), and monoclonal antibodies (mAbs) blocking immune-inhibitory pathways (e.g., anti-CTLA-4, anti-PD-1) can induce durable objective tumor regressions in patients with advanced unresectable melanoma, attesting to the potency of anti-melanoma immunity in tumor rejection.