Studies have identified proteomic and metabolomic signatures of resection,52 decreasing tumor-associated variant allele frequency (VAF) with cytoreduction,54 and, specific to IDH-mutant gliomas, increasing D-2-HG with disease progression (Figure 4A) (C. Riviere-Cazaux, T. Burns, personal communication, November 5, 2024). Here, IDH1 is linked to central nervous system cancer.