Differential Expression of HBx Protein in the Liver from Patients with Chronic hepatitis, Cirrhosis and Hepatocellular Carcinoma

Abstract

Background/aims : Hepatocellular carcinoma is frequently associated with hepatitis B virus infection and HBx protein is suspected to be the main cause of hepatitis B virus related hepatocellular carcinoma. But little is known about the time of the HBx protein expression during hepatocarcinogenesis. These issues, therefore, are addressed in this article. Methods : We examined HBx protein expression in the chronic active hepatitis, cirrhosis and hepatocellular carcinoma by the immunohistochemical method. Results : Among the patients with chronic active hepatitis, four (80%) were HBx protein positive in hepatocytes. In contrast, only one (6%) out of 16 liver specimens with hepatocellular carcinoma showed positivity for HBx protein, whereas four (25%) of suirounding cmhotic tissues showed HBx protein positivity. Thus, differential expression of HBx protein was observed in the livers during hepatocarcinogenesis. HBx protein was expressed mostly in the cytoplasm of hepatocytes. We also examined p53 protein and p21^(WAF1) protein expression in some of the hepatocellular carcinoma. P53 protein was found only in the nucleus of hepatocellular carcinoma cells (38%), and p21^(WAF1)' protein was also detected in some hepatocellular carcinoma tissues irrespective of HBx protein and/or p53 protein expression. Conclusions : These findings suggest that the HBx protein is expressed in the early stage of hepatitis B virus related hepatocarcinogenesis.