The expression of NKG2D, NKp30 and NKp44 was higher in a coculture of NK cells and HIF-1α-expressing HCC cells with apigenin treatment than without (Figs. 2A-2C, NKG2D+; CoCl2 18.54%, CoCl2+apigenin 24.49%, NKp30+; CoCl2 34.35%, CoCl2+apigenin 38.67%, NKp44+; CoCl2 9.49%, CoCl2+apigenin 11.2%, **p < 0.05). This evidence concerns the gene KLRK1 and hepatocellular carcinoma.