L Shen1, D Qui, J Fang. 1. Shanghai Institute of Digestive Disease, Shanghai Second Medical University.
Abstract
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). CONCLUSION: 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.
OBJECTIVE: To evaluate the molecular biological mechanism of humanhepatocellular carcinoma--DNA methylation pattern of certain oncogenes. METHODS: Methylation patterns of c-myc, c-N-ras oncogenes in humanhepatocellular 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). CONCLUSION: 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.