Fig. 1

Higher global DNA methylation levels are frequently found in high-grade EOC. a Heatmap visualization constructed using k-means clustering of differential methylation positions (DMPs:14120) (5% false discovery rate) with at least a 20% difference in the methylation level between low- and high-grade across 80 EOC. b Boxplot visualization of comparison of DMP methylation levels of low- and high-grade EOC. The median DMP methylation levels were 0.445 and 0.637 in the low- and high-grade groups, respectively. P value (****P < 0.0001) was computed by the Wilcoxon test. c Boxplot visualization of comparisons of DMP methylation levels of low- and high-grade DMPs, as well as the associated hypermethylated and hypomethylated DMPs. The median value of each group is shown as a line of each box and number. P value (****P < 0.0001) was computed by the Wilcoxon test. d Manhattan plot of differentially methylated positions, where each point represents the observed − log10-adjusted P value at each CpG site. A total of the top 16 significant DMPs (annotated to 17 DMP-associated genes) (adjusted P < 5*10⁻¹¹) found on the relevant gene promoter regions were marked. e Volcano plot showing the distribution of 11,986 hypermethylated DMPs (red) and 2134 hypomethylated DMPs (blue) with FDR-adjusted P < 0.05 and difference in β value (|logFC|> 0.2). Dashed lines represent cutoffs for the significant DMP-associated genes. The most differentially regulated genes of hypomethylated and hypermethylated sites are marked. (F) DMR at the promoter regions of CLDN16 and HPS4. Results are plotted in comparison of DNA methylation levels of each CpG site located in the promoter regions CLDN16 and HPS4 in low- and high-grade EOC