CD8A and cancer: One of the eminent mechanisms that has been at the center of attention during recent decades is the existence of an inhibitory regulatory CD4+FoxP3+ T cell population in higher proportions that predisposes patients to various cancers, probably because regulatory T cells (Tregs) generate cytokines with immunosuppressive traits, for instance, TGF-β and IL-10 that restrict CD8+ T cell activity and differentiation [52,53,54].