Importantly, treatment with the DNA methyltransferase inhibitor 5-Azacytidine (5-AzaC) and the histone deacetylase inhibitor trichostatin A (TSA) significantly upregulated PHD3 expression in glioma cell lines with a methylated promoter (Fig. 1f, Supplementary Fig. 1g), supporting the role of promoter methylation in the control of PHD3 expression. Here, EGLN3 is linked to glioma.