Mutant IDH1 1p/19q-codel gliomas frequently harbor TERT promoter (TERTp) and CIC mutations, and are associated with oligodendrogliomas; whereas mutant IDH1-non-codel harbor mutations in alpha-thalassemia X-linked mental retardation (ATRX) and TP53, and associated with astrocytoma and oligoastrocytoma (Cancer Genome Atlas Research et al., 2015; Bai et al., 2016; Ceccarelli et al., 2016; Louis et al., 2016; Venteicher et al., 2017). Here, IDH1 is linked to oligodendroglioma.