Inaddition, the phosphorylated form of RXRα(p-RXRα)is also resistant to ubiquitination and subsequent proteasome-mediated breakdownin both human HCC tissues and a human HCC cell line, whereas RXRαprotein is unphosphorylated and highly ubiquitinated in the normal liver and innonproliferating hepatocyte cultures [26]. This evidence concerns the gene RXRA and hepatocellular carcinoma.