IFNG and neoplasm: Both cytotoxic activity and IFN-γ production by CTL recognizing tumours are critical for cancer immunoediting, however, whether IFN-γ is anti-tumorigenic5, 6, 7, 8, 9, 10, 11 or pro-tumorigenic12, 13, 14, 15, 16 remains controversial17, 18, 19.