We would like to thank Nuray Bogurcu and Marion Ross for help with the tumour injections and processing, Sabine Gräf-Höchst and Marietta Wolter for help with the analysis of PHD3 promoter methylation, Bernhard Radlwimmer for help with gene copy number and expression data analysis in primary glioma specimens and Emil Karaulanov for advice on bioinformatic analysis. Here, EGLN3 is linked to glioma.