Fig A2.

Glioblastomas (GBMs) with mutations in isocitrate dehydrogenase 1 (IDH1) at R132 (IDH1^R132MUT; IDH1MUT) are restricted from Mesenchymal gene expression. Gene expression analysis reveals a robust positive association of IDH1^R132MUT high-grade astrocytomas with the Proneural signature and an absolute exclusion of the Mesenchymal gene signature from IDH1^R132MUT tumors. Subtypes and their respective centroids are labeled as follows: Proneural (PN), Proliferative (PROLIF), and Mesenchymal (MES). (A) The three-dimensional graphical plot illustrates the similarity between individual tumor samples in cohorts C and G to each of the three centroids created by K means clustering to define tumor subtypes.¹⁹ (B) Matched primary and recurrent pairs of tissue show that IDH1^R132MUT GBMs and anaplastic astrocytomas (AAs; grade 3 astrocytoma) fail to acquire a Mesenchymal gene expression signature on recurrence (Data Supplement). IDH1WT, IDH1^R132WT.