Array-based profiling of the differential methylation status of CpG islands in hepatocellular carcinoma cell lines

Alterations in the DNA methylation status particularly in CpG islands are involved in the initiation and progression of many types of human cancer. A number of DNA methylation alterations have been reported in hepatocellular carcinoma (HCC). However, a systematic analysis is required to elucidate the relationship between differential DNA methylation status and the characteristics and progression of HCC. In the present study, a global analysis of DNA methylation using a human CpG-island 12K array was performed on a number of HCC cell lines of different origin and metastatic potential. Based on a standard methylation alteration ratio of ≥2 or ≤0.5, 58 CpG island sites and 66 tumor-related genes upstream, downstream or within were identified. This study showed a series of CpG island methylation alterations in the HCC cell lines. The expression of various oncogenes, tumor suppressor genes and other key genes were up- or downregulated, respectively, resulting in CpG island hypomethylation or hypermethylation accordingly. To conclude, a foundation has been provided for screening CpG island methylation profiles as HCC biological markers.