This work is made possible by the patients and their families whom generously contributed to this study. This work is supported by the National Brain Tumor Society, Oligo Research Fund; Cancer Center Support grants P30CA16672 and P30CA034196; Cancer Prevention & Research Institute of Texas (CPRIT) grant number R140606; Agilent Technologies (R.G.W.V.); the National Institutes of Health- National Cancer institute for the following grants: NCI CA170278 (L.M.P., T.M.M., H.N.), NCI R01CA222146 (L.M.P., H.K.N.), NCI R01CA230031 (J.H.C., J.N.), NCI R01CA188288 (J.S.B.-S., R.B., P.B., K.L.L., A. Chakravarty., A.E.S.), R01CA179044 (A. Iavarone), U54CA193313 (A. Iavarone). The National Brain Tumor Society (W.K.A.Y., J.F.d.G.). Brain Tumour Northwest tissue bank (including the Walton research tissue bank) is supported by the Sidney Driscol Neuroscience Foundation and part of the Walton Centre and Lancashire Teaching Hospitals NHS Foundation Trusts (A.F.B., M.D.J.). This work was supported by a generous gift from the Dabbiere family (J.F.C.). Support is also provided by a Leeds Charitable Foundation grant (9R11/14-11 to L.F.S.), University of Leeds Academic Fellowship (11001061) (L.F.S.) and Studentship (11061191) (G. Tanner) as well as Leeds Teaching Hospitals NHS Trust (A. Chakravarti, A. Ismail). The Leeds Multidisciplinary Research Tissue Bank staff was funded by the PPR Foundation and The University of Leeds (S.C.S.). Funds were received from The Brain Tumour Charity (C.W., grants 10/136 & GN-000580, B.A.W., 200450). Ghazaleh Tabatabai is funded by EKFS 2015_Kolleg_14. R01CA218144 (P.S.L., E.J.C., J.C., A.K.L.) and Strain for the Brain, Milwaukee, WI (P.S.L., E.J.C., J.C., A.K.L.). E.K. is recipient of an MD-Fellowship by the Boehringer Ingelheim Fonds and is supported by the German National Academic Foundation. The Leeds Multidisciplinary Research Tissue Bank staff was funded by the PPR Foundation and part of the University of Leeds (S.C.S.). GLASS-Austria was funded by the Austrian Science Fund project KLI394 (A.W.). GLASS-Germany was funded by the German Ministry of Education and Research (BMBF) 031A425 (G. Reifenberger, P.L.) and German Cancer Aid (DKH) 70-3163-Wi 3 (M.W.). GLASS-NL receives support from KWF/Dutch Cancer Society project 11026 (M.C.M.K., P.W., R.G.W.V., P.J.F., J.M.N., M. Smits, B.A.W.). We thank the University of Colorado Denver Central Nervous System Biorepository (D.R.O.) for providing tissue samples. Sponsoring was also received from the National Institute of Neurological Disorders and Stroke (NINDS R01NS094615, G. Rao), F.S.V. is supported by a postdoctoral fellowship from The Jane Coffin Childs Memorial Fund for Medical Research. F.P.B. is supported by the JAX Scholar program and the National Cancer Institute (K99 CA226387); K.C.J. is the recipient of an American Cancer Society Fellowship (130984-PF-17-141-01-DMC). We thank the Jackson Laboratory Clinical and Translation Support team for coordinating all data transfer agreements. We thank M. Wimsatt for assistance in graphic design.