Upon successful activation, CD8+ T cells differentiate into effector T cells, also known as cytotoxic T lymphocytes (CTLs), that after recognition of the cancer cells expressing the tumor antigen of interest, induce their killing, mainly through secretion of cytotoxic molecules such as perforin and granzymes, and/or by direct contact through Fas ligand (FasL)-mediated interactions (83). This evidence concerns the gene CD8A and neoplasm.