CYP1A1 and hepatocellular carcinoma: Epigenetic mechanisms also largely determine the induction ratios of CYP1A1 and CYP1B1 in various human and mouse cell lines upon TCDD treatment [84,85,86], and histone H3 phosphorylation at serine-10 in the DRE of Cyp1a1 was demonstrated to be a prerequisite for the induction of Cyp1a1, Aldh3a1, and Nqo1 in TCDD-treated mouse hepatoma cells, presumably via chromatin remodeling [87].