CD274 and cancer: There are many negative influences on the biological responses to T-cells including the upregulation of check-point molecules like PD-1/PD-L1 and PD-L2, expression of suppressive cytokines like VEGF and TGF-β, the infiltration of myeloid-derived suppressive cells, tumor associated macrophages, cancer associated fibroblasts and regulatory T-cells, poor vascularization and hypoxic conditions [425].