Since AhR has been reported to modulate the phenotype of mouse hepatoma cells in the absence of exogenous ligands (Ma and Whitlock, 1996), it was of interest to further elucidate the potential mechanisms by which AhR exerts its effects on the phenotype of cells, and to identify AhR target genes in the absence of exogenous ligands. Here, AHR is linked to hepatocellular carcinoma.