Clonal origin of hepatitis B virus-associated hepatocellular carcinoma.

The clonal origin of tumors was studied in two multifocal hepatocellular carcinomas arising from hepatitis B viral cirrhosis. DNA extracted from several tumor nodules was analyzed for the presence of hepatitis B virus genome by the Southern blot technique. Unique clonal integration of the viral DNA sequences occurred in both cases. In each case, identical integration bands occurred among multiple nodules of liver tumor. These results are strong evidence of a unicentric origin of these tumors, although the tumors' gross appearance is suggestive of multifocal origin.