NOS2 and neoplasm: The density of NOS2 macrophages was higher in PBS injected controls (28.7 ± 2.8, mean ± SEM cells/mm2) compared to tumor-derived EV injected prostates (G-EVs; 19.4 ± 1.5, P = 0.02, MLL-EVs; 19.7 ± 3.5, mean ± SEM cells/mm2, P = 0.055), suggesting that tumor-derived EVs decrease the number of tumoricidal M1 macrophages.