To verify that the downregulation of methylation levels of TNC in gliomas is mediated by active DNA demethylation of TDG, we confirmed by ChIP- qPCR assay that TDG was able to combine with the chr9: 117826025 position of TNC, participate in the DNA demethylation process of TNC (Fig. 3F). This evidence concerns the gene TNC and central nervous system cancer.