KDR and neoplasm: By detecting the expression of intracellular IFN-β within tumor-cell-derived single cells, the authors revealed that IFN-β-producing cells in the tumor express low levels of CD45 (a general marker of hematopoietic cells) but high levels of CD31 and vascular endothelial growth factor receptor 2 (VEGFR-2) (the specific marker of endothelial cells), suggesting that activation of STING pathway by exogenous STING agonists in endothelial cells, instead of DC cells or other immune cells, facilitate the infiltration of CD8+ T cells into the tumor microenvironment [36].