When hepatoma cells were treated with IL-6, the levels of CYP1A1, CYP1A2, CYP2B6, CYP3A3, and CYP3A4 mRNAs were markedly suppressed, as well as activities of CYP1A2, CYP2B6, and CYP3A4 (Fukuda et al., 1992; Fukuda and Sassa, 1994; Rubin et al., 2015). This evidence concerns the gene CYP3A4 and hepatocellular carcinoma.