HIF1A and hepatocellular carcinoma: Unexpectedly, the quantity of IFN-γ in the supernatant of a coculture of NK-92 cells and HCC cells significantly increased when HIF-1α was expressed by treatment with CoCl2 (250 μM) as compared with no expression of HIF-1α, and apigenin conversely rather decreased the level of IFN-γ (Fig. 5A; *, **p < 0.05).