Fig. 7.

Roles of cancer cells and immunosuppressive cells in tumor immune microenvironment. Immunosuppressive cells in the TME, such as Tregs, M2 macrophages, myeloid-derived suppressor cells, PD-L1-positive DCs, cancer-associated fibroblasts, and tumor cells form a suppressive ecological niche at the tumor site through the expression of immunosuppressive signals. TME Tumor microenvironment, Tregs Regulatory T cells, PD-L1 Programmed cell death-ligand 1, DC Dendritic cell, CTLA4 Cytotoxic T-lymphocyte-associated antigen 4, MHC Major histocompatibility complex, Teff, Effector T cell, IL Interleukin, ROS Reactive oxygen species, NK Natural killer cells, iNOS Inducible nitric oxide, Arg-1 Arginase 1, TGF-β Transforming growth factor-β, PEG2 Prostaglandinum E-2, CCL22, C-C motif chemokine ligand 22, EGFR Endothelial growth factor receptors, EMT Epithelial-mesenchymal transition, CXCL14 CXC-chemokine ligand 14, TAM Tumor-associated macrophage, VEGFR Vascular endothelial growth factor receptors