Overrepresentation of genes with an inverse correlation between CpG site methylation and gene expression levels among genes highlighted in the study. The Pearson correlation coefficients for the methylation levels and expression levels for (A) all 391 genes analyzed in this study and (B) 99 genes highlighted by methylation analysis in the study are shown on the horizontal axis, and the numbers of genes in each bin of correlation coefficients are shown on the vertical axis. The thin bars marked in gray indicate the upper and lower probability limits (P < .01) for random distribution of correlation coefficients according to 10 000 permutations per gene. The histogram shows that there is an overrepresentation of genes with an inverse correlation between methylation and gene expression levels, which is unlikely to occur by chance, both among all genes analyzed in the study and the genes highlighted by methylation analysis. A larger proportion of genes highlighted by methylation analysis have an inverse correlation with the total expression levels (56%) than that of all analyzed genes (33%). The data underlying the histogram is available in supplemental Table 7.