IDH1 and central nervous system cancer: To assess the contribution of glioma-relevant pathways to IDH-mutant gliomagenesis, immortalized human astrocytes conditionally expressing IDH1R132H were treated simultaneously with doxycycline for IDH1R132H induction and the following compounds: CHIR99021 targeting GSK3/WNT signaling, YO-01027 targeting γ-secretase/NOTCH signaling, and Repsox targeting ALK5/TGF-β signaling to modulate the respective pathways (Fig. 1a).