ABCB4 and cancer: The upregulation of CAR expression in HCC as well as the over-representation of CAR motifs in the cis-regulatory elements that were selectively hyper-acetylated in cancers as compared to inflamed livers, suggest the hypothesis that transformed hepatocytes have acquired the ability to efficiently detoxify bile acids, which in turn would explain their ability to survive and proliferate in the context milieu of Mdr2-/- livers.