IDH1 and neoplasm: Consistent with previous studies, we found that a subset of patient tumours (~18%) expressed high levels of SOX10. SOX10 high tumours were enriched for the proneural, but also included mesenchymal and classical transcriptional subtypes, as well as IDH1 mutant tumours, suggesting that pre-oligodendrocyte differentiation may occur across all GBMs (Supplementary Fig. 2a, b)9.