Figure 1

Representative results of methylation analyses by MALDI-TOF MS and pyrosequencing. (A and B) Representative samples of aberrant hypomethylation. KvDMR1 of HB08 and PEG10 of HB11 are shown. KvDMR1 was hypomethylated in both adjacent normal liver and tumor tissues, whereas PEG10-DMR was hypomethylated only in tumor tissue. (C and D) Representative samples of aberrant hypermethylation. INPP5Fv2-DMR in HB05 and RB1-DMR in HB11 are shown. Only tumors showed hypermethylation at these DMRs. Aberrant methylation of a DMR was defined as when more than 60% of total CpG units or CpG sites were aberrantly methylated. Aberrant methylation of a CpG unit or CpG site was defined as occurring when the difference of its methylation indexes in two samples exceeded 0.15. The vertical axis represents the methylation index; the horizontal axis represents CpG units (MALDI-TOF MS) or CpG sites (pyrosequencing) analyzed. Green line: average of normal control livers; blue line: adjacent normal liver; red line: tumor (hepatoblastoma).