The important immune cells implicated in the elimination of tumor are natural killer (NK) cells, T helper 1 (Th1) cells, monocytes and CD8 + T cells, whereas several immune cell subsets including neutrophils, myeloid-derived suppressor cells (MDSC) and regulatory T cells (Treg) have the ability to facilitate tumor development [20]. The gene discussed is CD8A; the disease is neoplasm.