Abstract
The polymerase chain reaction in situ hybridization (PCR-ISH) is a new technique
that combines the sensitivity of PCR with the localizing ability of ISH. To
investigate the expression pattern of hepatitis B virus (HBV) in the tissue of
hepatocellular carcinoma (HCC), we detected HBV-DNA with PCR-ISH in
paraffin-embedded tumor and corresponding non-tumor tissues from 11 HCC
patients. HBV-DNA was detected in 4 of 11 tumor tissues and in 7 of 10 non-tumor
tissues. In tumor tissues, positive signals were scattered in the tissue with
occasional clustering, and were found mainly in the cytoplasm of HCC cells
rather than in the nucleus. In non-tumor tissues, the number of positive signals
was higher than in tumor tissues and they were found in regenerating nodules
with differing patterns and intensities. When we compared the detection rate of
PCR-ISH with nested PCR among 10 tissue samples, HBV-DNA was detected in 5
tissue samples by PCR-ISH, but the S gene was detected in 10, precore gene in 9
and X gene in 8 by nested PCR. The findings suggest that PCR-ISH is a sensitive
technique for localizing HBV in tissue sections and that the low level of HBV
replication persists in HCC cells.