| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1989: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1988: ¥800,000 (Direct Cost: ¥800,000)
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| Research Abstract |
Numerous epidemiological studies indicated a striking correspondence between areas where frequency of hepatocellular carcinoma (HCC) is high and where hepatitis B virus (HBV) is endemic. Recently, besides serological evidence, the integration of HBV DNA in HCC has been demonstrated using molecular hybridization technique. However, little is known about the integration in HBV carriers, particularly in childhood. Here, we focused on the presence of HBV DNA in liver tissues of HCC, chronic hepatitis and asymptomatic carriers in childhood.
The samples were obtained by biopsy and used for DNA extraction. Purified DNA was digested with Hind III, subjected to agarose gel electrophoresis and analyzed by the Southern blot hybridization technique. The age of patients are between 5-15.
In 4 of 5 patients of chronic hepatitis, HBV DNA was integrated in the livers. Diffuse hybridization from 5.0 to 20 kb in size was observed, indicating multiple populations of integrated HBV DNA. All of 2 HCC cases (11 yrs old, male and female), HBV DNA was integrated in tissues. However, blot hybridization showed a sharp band in one, showing monoclonal growth of tumor cells, while diffuse smear from 7.6 to 20.0 kb was detected in the other samples. In 2 asymptomatic carriers, HBV DNA integration was also shown in one.
Using molecular cloning method, multiple integration pattern was confirmed in the latter case. In the cases of chronic active hepatitis, rearrangement of host-DNA including integrated proviral DNA were found in several patients. This rearrangement may be important for the accivation of cellular oncogene, such as c-myc.
From these results, the integration of HBV DNA was completed in early childhood in most, if not all, HBV carriers. For the early prediction of HBV-related HCC, long term follow-up using molecular biological technique may be necessary in HBV carriers, particularly in chronic hepatitis patients.
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