Notably, in the 2016 WHO classification of central nervous system (CNS) tumors, grade II/III astrocytomas are molecularly divided into IDH mutant, IDH wild-type, and not otherwise specified categories, emphasizing the diagnostic and prognostic value of IDH mutation status in glioma (Louis et al., 2016). Here, IDH1 is linked to astrocytoma (excluding glioblastoma).