VEGFA and cancer: Salmonella-mediated cancer immunotherapy profoundly affects the tumor microenvironment through several means: shifting macrophage phenotypes from M2 to M1 via toll-like receptors (TLRs) [9], initiating tumor cell apoptosis by inducing robust nitric oxide (NO) production in tumor cells [10], and inhibiting angiogenesis by downregulating vascular endothelial growth factor (VEGF) [11].