Integration of hepatitis B virus containing mutations in the core promoter/X gene in patients with hepatocellular carcinoma.
Integration of hepatitis B virus is thought to be an essential step in hepatitis B virus associated hepatocarcinogenesis. Mutations at nucleotides 1762 and 1764 in the hepatitis B virus, within a sequence encoding both the core promoter gene and the X gene, have been found frequently in patients with hepatocellular carcinoma. However, integration of these mutant sequences has not been reported to date.


METHODS
A 228-base pair segment of the hepatitis B virus core promoter gene was amplified from hepatocellular carcinomas and adjacent non-tumourous liver tissue by nested PCR and sequenced. Integration of hepatitis B virus into human genomic DNA was investigated using the 'genome walking' method.


RESULTS
Point mutations were found in both hepatitis B virus nucleotides 1762 and 1764 in 8 of 14 hepatocellular carcinoma tissues (57%) and in 11 of 14 adjacent non-tumourous liver tissues (79%). Three patients were evaluated using the 'genome walking' method; all were found to have hepatitis B virus DNA integrated in their hepatocellular carcinoma (two patients) and/or in their non-tumourous liver tissue (three patients). Integration occurred in all tissues near host genomic sites that are prone to integration. Hepatitis B virus was integrated at or near the hepatitis B virus DR1 site in all samples, and all contained truncated X gene sequences that have been reported to be capable of producing fusion transcripts with transactivation potential.


CONCLUSIONS
Integrated hepatitis B virus DNA containing core promoter mutations at nucleotides 1762 and 1764 was found in hepatocellular carcinoma and/or adjacent non-tumourous liver tissue of three patients. These findings leave open the possibility that insertional mutagenesis or transactivation by fusion transcripts resulting from hepatitis B virus integration could play a role in hepatocarcinogenesis in some patients.
Momosaki
S
S
Division of Emerging and Transfusion Transmitted Diseases, Food and Drug Administration, Center for Biologics Evaluation and Research, 1401 Rockville Pike, HFM-300, Rockville, MD 20852-1448, USA.
Hsia
C C
CC
Nakashima
Y
Y
Kojiro
M
M
Tabor
E
E
D000368:Aged; D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000821:virology; D016022:Case-Control Studies; D004279:DNA, Viral / Q000032:analysis; D005260:Female; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000821:virology; D008297:Male; D008875:Middle Aged; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D017422:Sequence Analysis, DNA; D014758:Viral Core Proteins / Q000235:genetics*; D016662:Virus Integration / Q000235:genetics*
D004279:DNA, Viral; D014758:Viral Core Proteins