| Research Abstract |
Using the molecular biological methods, we examined the loss of heterozygosity (LOH) on chromosomes 13q, 16q and 17p, which are frequently detected in human hepatocellular carcinoma (HCC). We also examined the gene expression of antimetastatic gene, nm23H1, adhesion molecules, cell adhesion regulator (CAR) and E-cadherin (EC) which are associated with cancer metastasis. Finally, we analyzed the relationships between these factors and clinicopathological features and DNA ploidy pattern. Our results were as follows ;
1.The frequency of LOH,especially 16q chromosome and reduced expression of nm23H1, CAR,EC gene were increased along with the progression of the Stage of HCC.
2.CAR and EC genes also existed on 16q chromosome and their frequency of reduced expression was higher in those tumors with LOH of 16q chromosome.
3.In tumors with 2 and more LOH,including 16q chromosome, and reduced expression of nm23H1, CAR,EC,the frequency of portal vein invasion, intrahepatic metasstasis, aneuploid, mu
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ltiple intrahepatic recurrence, and extrahepatic metastasis were high.
4.We were able to confirm the multicentric occurence of HCC by analysing the differences of LOH pattern of tumors of multinodular HCC and primary and recurrent tumors in the resected specimens of recurrent HCC.
Thsese investigations demonstrated that molecular biological analysis was very useful to evaluate the grade of malignancy and diagnose muticentric occurence in HCC.With polymerase chain reaction (PCR) method with microsatellite marker for LOH and reverse transcriptase PCR (RT-PCR) method for gene expression, we can analyze a very small amount of sample, such as those obtained by needle biopsy, and thus, try to evaluate the prognosis preoeratively. As these genetic alteration occures in the late stage of HCC,it is important to investigate the genetic alteration in the early stage. Thus we plan to study the LOH in the early stage to identify new tumor suppressor genes on these chromosomes, and the relationship with abnormal DNA repair genes, detected in those who had hereditary nonpolyposis colorectal cancer, which causes carcinogenesis and progression of HCC. Less
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