IDH1 and oligodendroglioma: Turkalp et al. (2014) found that IDH1/2, as an early event in the development of glioma, provided some reference in predicting glioma. Akagi et al. (2018) also showed that oligodendroglioma patients with IDH-mutant and 1p/19q co-deleted, rather than the WHO grade, demonstrated a better overall survival.