The amount of intracellular perforin of NK cells cocultured with HCC cells was significantly reduced by the blocking of IL-6 (Fig. 2B, Non-treated 68.81%, Anti-IL-6 49.42%, *p < 0.05) but mRNA of perforin was no difference (Fig. 3C, ns). The gene discussed is PRF1; the disease is hepatocellular carcinoma.