Figure 2.

Most common immune evasion strategies by tumor cells: (i) Secretion of immune-suppressor molecules (i.e., CTLA4 and PD1/PDL1); (ii) production and polarization of M2 macrophages; (iii) abnormal antigen presentation by MHC-I and MHC-II molecules; (iv) negative stimulation of TCR signaling pathway by downregulation of antigenicity and upregulation of anergic TME; (v) low immunogenicity of TAA; (vi) T-cell apoptosis and induction of CTL death; (vii) attraction and induction of Tregs and depletion of NK cells; (viii) attraction and polarization of MDSCs, immature DCs, and precursor DC.