The significance of hepatitis B virus DNA detected in hepatocellular carcinoma of patients with hepatitis C

Abstract

Recently, it has been reported that hepatitis B virus (HBV) DNA is detected in cancerous liver tissues in some hepatitis B surface antigen negative chronic hepatitis C patients with hepatocellular carcinoma (HCC). However, the significance of HBV DNA detected in such cases remains unclear. The authors determined the presence or absence and the titers of HBV DNA in the liver tissue of anti-hepatitis C virus (HCV) positive/HBs antigen negative patients with HCC by polymerase chain reaction (PCR) and Southern hybridization, and correlated them with clinicopathologic parameters. HBV DNA was found in cancerous liver tissues from 12 (50.0%) of the 24 patients studied. However, Southern hybridization of genomic DNA in the cancerous liver tissues led to detection of HBV DNA in only 3 (12.5%) of the 24 patients, suggesting that the copy number of HBV DNA may be very low in most cases. Indeed, the titration of HBV DNA in cancerous liver tissues performed by the end point dilution method revealed that most contained less than one copy of HBV DNA per cell, although cells of monoclonal origin carrying integrated HBV DNA should have at least one copy of it. There was no significant difference in HBV DNA positivity between the HCC patients with and without underlying cirrhosis. The results of this study corroborate previous reports of frequent detection of HBV DNA in the liver tissue of anti-HCV positive/HBs antigen negative patients with HCC, but do not support an essential role of HBV in hepatocarcinogenesis in patients with chronic hepatitis C and occult HBV infection.