Increasing Incidence of Hepatocellular Carcinoma Possibly Associated with Non-A, Non-B Hepatitis in Japan, Disclosed by Hepatitis B Virus DNA Analysis of Surgically Resected Cases

At the National Cancer Center Hospital in Japan, the total number of surgically treated hepatocellular carcinomas (HCCs) has been increasing steadily and rapidly over the last 10 years, whereas the number of cases positive for hepatitis B surface antigen in sera (HBsAg) has remained almost stable. Thus, the relative percentage of HCC cases with serum HBsAg has shown a marked decrease. In order to examine whether this increased proportion of HBsAg-seronegative patients carries hepatitis B virus (HBV) DNA in the liver, we extracted DNA from the formalin-fixed and paraffin-embedded cancerous and noncancerous liver tissues of 79 patients with HCC. The HCCs examined included 49 specimens resected during a period from 1970 to 1980 and 30 resected in 1986 and 1987. We were able to detect reliably the presence of HBV DNA by dot-blot hybridization. The presence of HBV DNA in liver tissues showed a good correlation with positivity for serum HBsAg in both examined groups. In total, HBV DNA was detected in 81% (21 of 26) of HBsAg-seropositive cases and in only 8% (4 of 53) of HBsAg-seronegative cases, indicating that the increased number of HBsAg-seronegative cases had no HBV involvement. Among these HBsAg-seronegative HCC patients, 89.7% showed a histology of cirrhosis or chronic active hepatitis in the noncancerous liver and 29.1% had a history of blood transfusion. These results suggest an increasing incidence of non-A, non-B hepatitis-associated HCCs in Japan and the possible transmission of factors by means other than blood transfusion.