Consistent with previous studies5, 6, our results using Huh-7.5 hepatoma cells suggest that both STAT1 and STAT2 are involved in the early induction of ISGs in response to IFN-α, most likely through the formation of ISGF3, but that when IFN-α stimulation is prolonged, ISGs can be induced by a STAT2-dependent, STAT1-independent pathway (Fig. 8). This evidence concerns the gene IRF9 and hepatocellular carcinoma.