IDH1 and oligodendroglioma: To assess the ability of the mutations reported by FM to accurately characterize an oligodendroglioma diagnosis, correlations between 1p19q codeletion status and hTERT promoter mutations, in addition to other oligodendroglial diagnostic markers (CIC and FUBP1 mutations) and astrocytic markers (ATRX and TP53 mutations), were described in 66 pretreatment IDH mutated samples that had 1p19q testing.