IDH1 and central nervous system cancer: According to the 2016 WHO classification, glioma can be classified into five subtypes, namely, IDH-mutant lower-grade gliomas (LGGs) with chromosome 1p/19q co-deletion, IDH-mutant LGGs without 1p/19q co-deletion, IDH wild-type LGGs, IDH-mutant glioblastomas (GBMs), and IDH wild-type GBMs (Cancer Genome Atlas Research,N.