title: Evaluation of IDH1 status in diffusely infiltrating gliomas by immunohistochemistry using anti-mutant and wild type IDH1 antibodies.
abstract: Glioma cells with the isocitrate dehydrogenase (IDH) 1 G395A mutation are strongly immunopositive for mIDH1(R132H), an antibody against mutant IDH1(R132H) (clone H09). However, we encountered some gliomas which were ambiguously positive for mIDH1(R132H) despite having the IDH1 G395A mutation. The aim of this study was to establish an evaluation procedure of IDH1 status by immunohistochemistry. Forty-three diffusely infiltrating gliomas were studied, and four of eight anaplastic oligoastrocytomas with the IDH1 G395A mutation were modestly or weakly positive for both the mIDH1(R132H) and an antibody against wild type IDH1, RcMab-1. Based on our staining results, the IDH1 expression of both wild and mutated types seemed to be codominant and also to be evenly suppressed under a certain condition. We propose a procedure for determining IDH1 status. If a glioma is weakly positive for mIDH1(R132H), immunohistochemistry for RcMab-1 should be performed. If the tumor cells are strongly positive for RcMab-1, the IDH1 G395A mutation is judged to be absent on the grounds that IDH1 expression is not suppressed. If the tumor cells are weakly positive for both mIDH1(R132H) and RcMab-1, then a conclusion should be made after DNA sequencing. This procedure is useful for practical evaluation of IDH1 status.
authors.affiliation: Department of Human Pathology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan. ikota@gunma-u.ac.jp.
authors.forename: Hayato
authors.initials: H
authors.lastname: Ikota
authors.affiliation: Department of Human Pathology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan.
authors.forename: Sumihito
authors.initials: S
authors.lastname: Nobusawa
authors.affiliation: Department of Diagnostic Pathology, Gunma University Hospital, Maebashi, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Arai
authors.affiliation: Department of Regional Innovation, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Yukinari
authors.initials: Y
authors.lastname: Kato
authors.affiliation: Department of Pathology, Saitama Medical University, Saitama, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ishizawa
authors.affiliation: Department of Pathology for Regional Communication, Kobe University, Kobe, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Hirose
authors.affiliation: Department of Human Pathology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma, 371-8511, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yokoo
mesh_terms: D000293:Adolescent; D000328:Adult; D000911:Antibodies, Monoclonal; D001932:Brain Neoplasms / Q000235:genetics*; D005260:Female; D015870:Gene Expression / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics*; D005910:Glioma / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D007521:Isocitrate Dehydrogenase / Q000235:genetics* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D017422:Sequence Analysis, DNA; D055815:Young Adult
chemical_list: D000911:Antibodies, Monoclonal; D007521:Isocitrate Dehydrogenase; C543588:IDH1 protein, human
keywords: Glioma; IDH1; Immunohistochemistry