Sequence analysis of the hepatitis B virus pre-C region in hepatocellular carcinoma [HCC] and nontumoral liver tissues from HCC patients.
We investigated whether replication-competent pre-C/C defective mutants of hepatitis B virus (HBV) are detectable in primary human hepatocellular carcinoma (HCC) tissues from patients of a geographic area endemic for such mutants. DNAs extracted from formalin-fixed paraffin-embedded HCC samples were checked for the presence of specific HBV DNA sequences using the polymerase chain reaction (PCR). Amplified pre-C regions from nine HCC samples were directly sequenced as were samples of nontumoral liver tissues from five of these patients. The data show that hypervariable distal pre-C sequences were present in all nine HCC samples; this high variability was dependent on point mutations, which led to amino acid substitutions in nearly all cases. Interestingly, seven of the nine HBV DNA-positive samples from HCC tissues (but not samples from peritumoral liver tissue) showed mutations leading to amino acid substitution at the level of a distal cysteine residue. No mutation generating a translationally defective pre-C/C region was detectable in the tumor samples. Otherwise, in four of the six nontumoral liver tissues available from the same patients, a pre-C sequence with an in-frame TAG stop codon was detectable, although in three cases as a component of mixed population.
Manzin
A
A
Institute of Microbiology, University of Ancona Medical School, Italy.
Menzo
S
S
Bagnarelli
P
P
Varaldo
P E
PE
Bearzi
I
I
Carloni
G
G
Galibert
F
F
Clementi
M
M
D000595:Amino Acid Sequence; D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000382:microbiology*; D005814:Genes, Viral; D006512:Hepatitis B Core Antigens / Q000235:genetics*; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D008099:Liver / Q000382:microbiology; D008113:Liver Neoplasms / Q000382:microbiology*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D015345:Oligonucleotide Probes; D016133:Polymerase Chain Reaction; D015678:Viral Structural Proteins / Q000235:genetics*
D006512:Hepatitis B Core Antigens; D009838:Oligodeoxyribonucleotides; D015345:Oligonucleotide Probes; D015678:Viral Structural Proteins