Tumor specific methylome in Chinese high-grade serous ovarian cancer characterized by gene expression profile and tumor genotype.

•A comparative DNA methylation profiling for HGSOC tumors and matched normal tissues combined with an extended validation.•A global tumor specific hypomethylation but with skewing towards hypermethylation in gene promoter was detected in HGSOC.•Integration of DNA methylation and expression data identified potentially functional methylation biomarkers for HGSOC.•An epigenetic subgroup of HGSOC with higher levels of DNA methylation was correlated with TP53 mutations.