title: IDH1 mutation is prognostic for diffuse astrocytoma but not low-grade oligodendrogliomas in patients not treated with early radiotherapy.
abstract: Despite accumulating knowledge regarding molecular backgrounds, the optimal management strategy for low-grade gliomas remains controversial. One reason is the marked heterogeneity in the clinical course. To establish an accurate subclassification of low-grade gliomas, we retrospectively evaluated isocitrate dehydrogenase-1 (IDH1) mutation in clinical specimens of diffuse astrocytomas (DA) and oligodendroglial tumors separately. No patients were treated with early radiotherapy, and modified PCV chemotherapy was used for postoperative residual tumors or recurrence in oligodendroglial tumors. Immunohistochemical evaluation of IDH status, p53 status, O(6)-methylguanine methyltransferase expression, and the MIB-1 index were performed. The 1p and 19q status was analyzed with fluorescence in situ hybridization. Ninety-four patients were followed for a median period of 8.5 years. For DAs, p53 was prognostic for progression- free survival (PFS) and IDH1 was significant for overall survival (OS) with multivariate analysis. In contrast, for oligodendroglial tumors, none of the parameters was significant for PFS or OS. Thus, the significance of IDH1 mutation is not clear in oligodendroglial tumors that are homogeneously indolent and chemosensitive. In contrast, DAs are heterogeneous tumors including some potentially malignant tumors that can be predicted by examining the IDH1 mutation status.
authors.affiliation: Department of Neurological Surgery, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba, 260-8670, Japan. iwadatey@faculty.chiba-u.jp.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Iwadate
authors.affiliation: Department of Neurological Surgery, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba, 260-8670, Japan.
authors.forename: Tomoo
authors.initials: T
authors.lastname: Matsutani
authors.affiliation: Department of Neurological Surgery, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba, 260-8670, Japan.
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Hirono
authors.affiliation: Department of Neurological Surgery, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba, 260-8670, Japan.
authors.forename: Shiro
authors.initials: S
authors.lastname: Ikegami
authors.affiliation: Department of Neurosurgery, Narita Red-Cross Hospital, 90-1 Iida-cho, Narita, Chiba, 286-8523, Japan.
authors.forename: Natsuki
authors.initials: N
authors.lastname: Shinozaki
authors.affiliation: Department of Neurological Surgery, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba City, Chiba, 260-8670, Japan.
authors.forename: Naokatsu
authors.initials: N
authors.lastname: Saeki
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001254:Astrocytoma / Q000235:genetics* / Q000532:radiotherapy; D001932:Brain Neoplasms / Q000235:genetics*; D002888:Chromosomes, Human, Pair 19; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007521:Isocitrate Dehydrogenase / Q000235:genetics*; D017567:Karnofsky Performance Status; D019394:Ki-67 Antigen / Q000378:metabolism; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D019853:O(6)-Methylguanine-DNA Methyltransferase / Q000378:metabolism; D009837:Oligodendroglioma / Q000235:genetics* / Q000532:radiotherapy; D011379:Prognosis; D011878:Radiotherapy / Q000379:methods*; D012189:Retrospective Studies; D016896:Treatment Outcome; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D055815:Young Adult
chemical_list: D019394:Ki-67 Antigen; D016159:Tumor Suppressor Protein p53; D007521:Isocitrate Dehydrogenase; D019853:O(6)-Methylguanine-DNA Methyltransferase
keywords: Diffuse astrocytoma; Early radiotherapy; Oligodendroglial tumor; Oligodendroglioma