[Correlation between hypomethylation of c-myc and c-N-ras oncogenes and pathological changes in human hepatocellular carcinoma].
OBJECTIVE
To evaluate the molecular biological mechanism of human hepatocellular carcinoma--DNA methylation pattern of certain oncogenes.


METHODS
Methylation patterns of c-myc, c-N-ras oncogenes in human hepatocellular carcinoma were studied by the Southern blot technique and HpaII/MspI restriction endonucleases. The pathological changes were also analyzed.


RESULTS
The c-myc and c-N-ras oncogene fragments were hypomethylated in DNA samples derived from cancerous (30.3% and 60.1%) and adjacent paracancerous (12.1% and 30.3%) liver tissues. Hypomethylation of c-myc gene in multifocal type was significant as compared with unifocal type (P < 0.05). It is also found that c-N-ras gene hypomethylation had a strong correlation with tumor size (P < 0.01).


CONCLUSIONS
The decrease of DNA methylation is present at the stage of liver carcinoma, and hypomethylation of c-myc, c-N-ras genes is correlated with the tendency of infiltration and metastasis.
Shanghai Institute of Digestive Disease, Shanghai Second Medical University.
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D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000473:pathology; D019175:DNA Methylation; D005260:Female; D016259:Genes, myc; D011905:Genes, ras; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis