Chronic exposure to antigen in the tumor microenvironment leads to high expression of inhibitory receptors, such as PD-1, TIM-3, CTLA-4, and LAG-3, as well as a gradual loss of the ability to produce effector cytokines (IFN-γ, TNF-α, and IL-2) and proliferate (7, 9). This evidence concerns the gene CTLA4 and neoplasm.