Fig. 2
From: Cancer vaccines as promising immuno-therapeutics: platforms and current progress
Resistance of cancer vaccines. a Tumor external resistance. Immunosuppressive cells (such as CAFs, MDSCs, Tregs, and M2 macrophages) and immunosuppressive cytokines can inhibit the activation of effector T cells and DC-mediated T cells directly or indirectly in TME. b Tumor intrinsic resistance. The intrinsic resistance of tumor contains six aspects: the mutations in signaling pathways supporting tumor-immune control; the loss of tumor antigen expression; the changes in antigen processing pathways; the loss of HLA expression; epigenetic changes; increased expression of immunosuppressive ligands c Immune selection: from immunosurveillance to tumor escape