title: Characterization of R132H mutation-specific IDH1 antibody binding in brain tumors.
abstract: Heterozygous point mutations of isocitrate dehydrogenase (IDH)1 codon 132 are frequent in grade II and III gliomas. Recently, we reported an antibody specific for the IDH1R132H mutation. Here we investigate the capability of this antibody to differentiate wild type and mutated IDH1 protein in central nervous system (CNS) tumors by Western blot and immunohistochemistry. Results of protein analysis are correlated to sequencing data. In Western blot, anti-IDH1R132H mouse monoclonal antibody mIDH1R132H detected a specific band only in mutated tumors. Immunohistochemistry of 345 primary brain tumors demonstrated a strong cytoplasmic and weaker nuclear staining in 122 cases. Correlation with direct sequencing of 186 cases resulted in consensus of 177 cases. Genetic retesting of cases with conflicting findings resulted in a match of 186/186 cases, with all discrepancies resolving in favor of immunohistochemistry. Intriguing is the ability of mIDH1R132H to detect single infiltrating tumor cells. The very high frequency and the distribution of this mutation among specific brain tumor entities allow the highly sensitive and specific discrimination of various tumors by immunohistochemistry, such as anaplastic astrocytoma from primary glioblastoma or diffuse astrocytoma World Health Organization (WHO) grade II from pilocytic astrocytoma or ependymoma. Noteworthy is the discrimination of the infiltrating edge of tumors with IDH1 mutation from reactive gliosis.
authors.affiliation: Department of Neuropathology, Institute of Pathology, Ruprecht-Karls-University Heidelberg, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Capper
authors.forename: Susanne
authors.initials: S
authors.lastname: Weissert
authors.forename: Jörg
authors.initials: J
authors.lastname: Balss
authors.forename: Antje
authors.initials: A
authors.lastname: Habel
authors.forename: Jochen
authors.initials: J
authors.lastname: Meyer
authors.forename: Diana
authors.initials: D
authors.lastname: Jäger
authors.forename: Ulrike
authors.initials: U
authors.lastname: Ackermann
authors.forename: Claudia
authors.initials: C
authors.lastname: Tessmer
authors.forename: Andrey
authors.initials: A
authors.lastname: Korshunov
authors.forename: Hanswalter
authors.initials: H
authors.lastname: Zentgraf
authors.forename: Christian
authors.initials: C
authors.lastname: Hartmann
authors.forename: Andreas
authors.initials: A
authors.lastname: von Deimling
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000937:Antigen-Antibody Reactions; D001254:Astrocytoma / Q000235:genetics* / Q000473:pathology; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D003001:Cloning, Molecular; D004273:DNA, Neoplasm / Q000096:biosynthesis / Q000235:genetics; D004806:Ependymoma / Q000235:genetics* / Q000473:pathology; D005260:Female; D005910:Glioma / Q000201:enzymology* / Q000235:genetics* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007521:Isocitrate Dehydrogenase / Q000235:genetics* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics / Q000502:physiology; D014176:Protein Biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
chemical_list: D004273:DNA, Neoplasm; D007521:Isocitrate Dehydrogenase; C543588:IDH1 protein, human