To determine the effect of chronic liver inflammation on liver DNA methylation, we measured global levels of 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) in the liver of Mdr2-KO and control Mdr2−/+ mice at the age of 12 months (late precancerous stage for mutants). The gene discussed is ABCB4; the disease is Hepatitis.