MDR1 gene expression in hepatocellular carcinoma and the peritumoral liver of patients with and without cirrhosis

P-glycoprotein (P-gp) and MDR1 mRNA expressions were assessed in tumoral and peritumoral specimens from patients with hepatocellular carcinoma (HCC) and in cirrhotic livers without HCC, using immunohistochemistry (C494 monoclonal antibody) and reverse transcription-polymerase chain reaction (RT-PCR) analysis. P-gp overexpression was detected in 24/28 tumoral livers (85%). In the peritumoral liver, staining was strong in cirrhotic nodules, and fainter in non-cirrhotic specimens. P-gp expression was as intense in the cirrhotic specimens free of HCC as in the peritumoral tissue of HCC developing in cirrhotic patients. These results were confirmed by RT-PCR analysis.