IFNG and cancer: Studies also show that TNF-α and IL-12 are co-stimulators for NK cells to produce IFN-γ [43], which is reported to work synergistically with TNF-α to generate reactive oxygen species and nitric oxide, which inhibit angiogenesis [33], activate macrophages and natural killer (NK) cells, and inhibit Treg cells [27,44], which suggests that these cytokines play substantial roles in cancer immunity.