CD8A and neoplasm: However, tumors can escape immune system surveillance by releasing immune-suppressive cytokines (e.g., TGF-β and IL-10) and soluble factors (e.g., kynurenine), by down-regulating major hystocompability complex (MHC) molecules, by loosing antigens, by inducing the expression of immune checkpoints (ICP) on CD8+ TILs (i.e., molecules that make T-lymphocytes anergic when engaged by the ICP ligands expressed on tumor cells), and by recruiting immune-suppressive cells such as T-regulatory (Treg) cells, myeloid-derived suppressor cells (MDSCs), and M2-polarized TAMs [145].