GCH1 and cancer: With regard to chromatin accessibility, although the global level in cancer cells varied for different patients (Fig. 1c), the Norm_epi_Adj and Norm_epi_Pri cells were clustered together but separated from the cancer cells based on the GCH methylation level in promoter regions, indicating comparable chromatin states between the Norm_epi_Adj and Norm_epi_Pri cells in gene promoter regions (Fig. 1e and Supplementary Fig. S6b).