Figure 3

CpGI28 of the MAOA promoter region is hypermethylated in cholangiocarcinoma. DNA was extracted from cell lines and human tissue and underwent bisulfite modification. Regions within the CpG islands were then amplified by PCR and the degree of methylation was assessed by pyrosequencing. Representative traces from the cholangiocyte cell line H69 and the cholangiocarcinoma cell line Mz-ChA-1 are shown (a) and the CpG residues within this sequence are designated R1 through R7. The degree to which each residue was hypermethylated for each cell line (b) or representative tumor tissue (c) was expressed on a grayscale. Average methylation for each sample was then correlated to the MAOA mRNA expression levels from each sample (d) and was significantly correlated (P=0.028) with a correlation coefficient of r=−0.532.