Reports published as early as 1996 and 1999 demonstrated that both BUT and trichostatin A, another inhibitor of HDAC, successfully restore expression of the AHR in hepatoma cells deficient in induction of CYP1A1 mRNA, as well as de-repress CYP1A1 expression in fibroblasts non-responsive to ligands of the AHR [59,60]. The gene discussed is CYP1A1; the disease is hepatocellular carcinoma.