IDH1 and glioma: Other studies provided a more nuanced view: in a series of lower-grade IDH-mutant gliomas [14], fluorescence positivity did not correlate with higher GTR rates (overall GTR 71%) but was instead associated with shorter OS (~2.5-fold higher risk of death, p = 0.009) and PFS (~2.5-fold higher risk of progression, p = 0.004).