| Research Abstract |
Thirty-six HCC tissues obtained from 34 patients were classified according to histological diagnosis into 6 well differentiated HCCs, 20 moderately differentiated HCCs and 10 poorly differentiated HCCs. High-molecular weight DNA was prepared form each tumor and the corresponding non-tumor tissue. Losses of heterozygosity (LOH) on chromosomes 4q, 5q, 10q, 11p, 16q 17p and mutation of the p53 and RB genes were simultaneously analyzed. They were composed of 3 cases of small HCC (the diameter of which was less than 3 cm) and 31 cases of advanced HCC.Twenty-seven of 34 (80%) patients analyzed had been exposed to hepatitis B virus (HBV) and/or hepatitis C virus (HCV). The frequencies of LOH on seven chromosomes were 57.9% in 17p13.3, 45.1% in 17p, 45.1% in 11p, 41.9% in 5q, 41.9% in 16q 24, 29.0% in 4q, 25.8% in 31 in advanced HCCs (4 of well differentiated, 18 of moderately differentiated and 9 of poorly differentiated carcinoma). On the contrary, LOH was observed on 4q, 5q, 16q, and 17p in
… More
33% (1/3) of the small HCCs (2 of well differentiated, and one of moderately differentiated carcinoma). The mutation of the p53 genes and polymorphism of the RB gene were present in 25.8% (8/31) and 12.9% (4/31) of the advanced tumor, respectively, but the mutation was not found in small HCC.LOH on every chromosome and p53 mutation were observed more frequently in more advanced tumors, and the genetic changes accumulated with the increase of the histological grade. These findings suggest that the accumulations of genetic changes in multiple tumor suppresser genes are involved in the progression of HCC.
We examined mutations of p53 by PCR-SSCP analysis and the configuration of HBV by genetic southern hybridization in 39 HCC tissues. Although there was no statistical significance in frequency of LOH and mutation of p53 between tumors from HBV-positive patients and those from HCV-positive patients, the frequency of the mutations of p53 in HBs antigen-positive sample (three of 15 (20%)) was slightly lower than that in HBs antigen negative sample (seven of 16 (44%)). The mutations were detected in HCCs that have integrated HBV DNA (three of 10) and no HBV DNA (eight of 22), but was not detected in the HCCs which had free HBV DNA (none of seven). These observations suggested that p53 and the HBV replications are associated with the development of HCC. Less
|
