title: Site-specific hypomethylation of the c-myc oncogene in human hepatocellular carcinoma.
abstract: In order to examine the effect of alteration in methylation of the c-myc gene on hepatocarcinogenesis, the extent of methylation of the c-myc gene was examined in 24 tissues of hepatocellular carcinoma (HCC), 24 adjacent non-tumor liver tissues from the same patients and 16 control liver tissues by the use of restriction endonucleases. The following results were obtained. (1) The c-myc gene from HCC tissue tended to be hypomethylated in comparison with that in non-tumor liver tissue from the same patient. (2) The c-myc gene from non-tumor liver tissue was hypomethylated to various degrees in comparison with that in control liver tissues. (3) The CCGG site in the third exon of the c-myc gene tended to be more extensively hypomethylated in HCC tissues than in non-tumor and control liver tissues. These results suggest that hypomethylation of the c-myc gene may occur to various degrees before the appearance of HCC, and may be associated with hepatocarcinogenesis. Moreover, the hypomethylation in the third exon of the c-myc gene is probably important for the development of HCC.
mesh_terms: D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000235:genetics*; D002460:Cell Line; D004273:DNA, Neoplasm / Q000378:metabolism; D003850:Deoxyribonuclease I / Q000378:metabolism; D005091:Exons; D006514:Hepatitis B Surface Antigens / Q000032:analysis; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics*; D008745:Methylation; D009857:Oncogenes; D013379:Substrate Specificity
chemical_list: D004273:DNA, Neoplasm; D006514:Hepatitis B Surface Antigens; D003850:Deoxyribonuclease I