IFNG and neoplasm: As already discussed above, IL-6, released by mononuclear phagocytes upon NB conditioning, and TGF-β1, produced by both immune and tumor cells, inhibit the IL-2-mediated activation of NK cells, through the activation of the STAT3 and SMAD2/3 pathways and suppression of IFN-γ, granzymes, and perforin release.