title: IDH1 mutation analysis in low cellularity specimen: a limitation of diagnostic accuracy and a proposal for the diagnostic procedure.
abstract: Recently, new techniques for detecting IDH1 mutations have been developed. Most studies assessed the mutation status in glioma tissue without consideration of the size of the samples. We assessed the mutation status of IDH1 in simulated small biopsied tissue from 5 low grade gliomas, prepared by grid cutting procedure with direct sequencing, IDH1 immunohistochemistry (IHC), multiplex PCR with single base extension (SBE) assay and PNA-clamping method, and then analyzed the agreement between the methods. Kappa values were 0.53 (direct sequencing), 0.59 (multiplex PCR with SBE assay), and 0.69 (PNA-clamping method). Discrepant results between the methods were observed in lower cellularity samples. Twelve out of 25 cases were classified as wild type by direct sequencing, even with IDH1 IHC-positive cells, whereas 6, 8, and 11 of IHC-negative cases were classified as mutant cases by other 3 methods. In conclusion, newly developed sensitive methods, such as the PNA-clamping method and multiplex PCR with SBE assay, are practically useful in addition to the conventional IDH1 IHC in small biopsied samples.
authors.affiliation: Department of Pathology, Yonsei University Wonju College of Medicine, Wonju, Republic of Korea.
authors.forename: Junjeong
authors.initials: J
authors.lastname: Choi
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Lee
authors.forename: Kyung-Jin
authors.initials: KJ
authors.lastname: Shin
authors.forename: Yang-Ki
authors.initials: YK
authors.lastname: Minn
authors.forename: Jieun
authors.initials: J
authors.lastname: Kim
authors.forename: Se Hoon
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm; D003951:Diagnostic Errors / Q000517:prevention & control*; D005260:Female; D005910:Glioma / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007521:Isocitrate Dehydrogenase / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009154:Mutation; D020135:Peptide Nucleic Acids / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods; D015203:Reproducibility of Results
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; D020135:Peptide Nucleic Acids; D007521:Isocitrate Dehydrogenase; C543588:IDH1 protein, human