IFNG and hepatocellular carcinoma: Therefore, we first determined the protein expression levels of SAMHD1 upon treatment with type I (IFNα, IFNβ) or type II interferons (IFNγ) in the hepatocellular carcinoma cell line HepG2, as well as in HepaRG, a human hepatic progenitor cell line that retains many characteristics of primary human hepatocytes (Fig. 6a,b).