Tregs, a subset of CD4+T cells [105], can induce dysfunction in CD8+T cells and facilitate immune evasion by tumor cells through IL-2 (enhance the proliferation and cytotoxic activity of CD8+T cells) deprivation, upregulation of PD-1 and CTLA-4 expression as well as IL-10 and TGF-β secretion, among other mechanisms [106]. This evidence concerns the gene PDCD1 and neoplasm.