IDH1 and astrocytoma (excluding glioblastoma): IDH1 expression was significantly higher in GBM IDH-wildtype (11.56 ± 0.58) compared to IDH-mutant (10.93 ± 0.43), now reclassified as grade IV astrocytoma IDH-mutant (Figure S1b, p-value = 2.6 × 10−3).