Hepatitis B virus DNA in liver and white blood cells of patients with hepatoma

Abstract

Hepatitis B virus (HBV) DNA was studied in liver DNA of 23 patients with primary hepatocellular carcinoma and in white blood cell DNA of 11 of these patients by Southern blot hybridization analysis probed with 32P-labeled HBV DNA cloned in plasmid pBR325. Of the 23 hepatoma DNA samples, 16 were positive for HBV DNA, and 15 of these showed integration of HBV DNA into the host liver DNA. In 5 patients, free HBV DNA was found in addition to integrated HBV DNA and in only one was free HBV found alone. All patients serologically positive for HBV surface antigen (HBsAg) were positive for HBV DNA in tumor samples. The pattern and the degree of hybridization differed considerably among different cases. HBV DNA was found in tumor and in adjacent nontumor tissue in two patients. Of 11 white blood cell DNA samples, two were positive for HBV DNA. The HBV DNA in the white blood cells was not integrated into the host DNA. In the undigested white blood cell DNA, the free HBV DNA gave a positive signal at 5.5 kb and often also at 9.5 kb. After Eco RI digestion, these 5.5-kb and 9.5-kb positive fragments disappeared, while a strong positive band at 3.2-kb appeared. Hind III digestion produced the same positive fragments as in the undigested white blood cell DNA and failed to produce the 3.2-kb fragment. Sometimes, especially after Hind III digestion, a positive fragment at a position corresponding to about 16.2 kb was also demonstrable in addition to the 5.5-kb and 9.5-kb positive fragments.(ABSTRACT TRUNCATED AT 250 WORDS)