CD274 and neoplasm: MDSCs can accumulate in the tumor microenvironment and peripheral immune organs in response to excess VEGF and suppress T cell and DCs functions through multiple mechanisms (76); (3) Expression of inhibitory immune proteins: in response to pathological angiogenic stimuli, the expression of programmed cell death ligand 1 (PD-L1) is upregulated on M2-type TAMs, aberrant phenotypic vascular endothelial cells, and tumor cells.