To test this in rGBM, we sequenced RNA from all available pre-treatment tumor biopsy tissue samples in the PVSRIPO cohort (Supplementary Fig. 4, n = 14, all IDH1-wt); we also tested other previously sequenced IDH1-wt rGBM cohorts (refs. 10,16, and TCGA). Here, IDH1 is linked to neoplasm.