IDH1 and astrocytoma (excluding glioblastoma): We found that the slopes were maximally different at subtype-specific VAF inflection points: TERT VAF = 0.18 for IDHwt GBM, IDH VAF = 0.325 for IDHmut astrocytoma, and IDH VAF = 0.30 for IDHmut oligodendroglioma (Supplementary Figures S2C, S2F, and S2I, respectively).