Marc Barritault1,2,3, Thiébaud Picart2,3,4, Delphine Poncet1,3, Tanguy Fenouil5, Anne d'Hombres6, Mathieu Gabut2, Jacques Guyotat4, Emmanuel Jouanneau4, Roxana Ameli7, Bastien Joubert8, Nathalie Streichenberger5,9, Alexandre Vasiljevic5, Jérôme Honnorat8, David Meyronet2,3,5, François Ducray2,3,8. 1. Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Cytologie et d'Anatomie Pathologique, Département de Biopathologie Moléculaire, Lyon, France. 2. Centre de recherche en Cancérologie de Lyon, INSERM U1052, CNRS UMR 5286, Cancer Cell Plasticity department, Transcriptome Diversity in Stem Cells laboratory, Lyon, France. 3. Université Lyon, Université Claude Bernard Lyon 1, Lyon, France. 4. Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Neurochirurgie Lyon, France. 5. Hospices Civils de Lyon, Groupement Hospitalier Est, Service de Cytologie et d'Anatomie Pathologique, Département de Neuropathologie, Lyon, France. 6. Hospices Civils de Lyon, Centre Hospitalier Lyon Sud, Département de Radiothérapie, Lyon, France. 7. Hospices Civils de Lyon, Groupement Hospitalier Est, Hôpital Neurologique, Service de Neuro-radiologie, Lyon, France. 8. Hospices Civils de Lyon, Groupement Hospitalier Est, Hôpital Neurologique, Service de Neuro-oncologie, Lyon, France. 9. Université Lyon, Université Claude Bernard Lyon 1, Institut NeuroMyogène CNRS UMR 5310 - INSERM U1217, Lyon, France.
Abstract
BACKGROUND: Biopsies in patients with a suspected glioma are occasionally nondiagnostic. OBJECTIVE: To explore the utility of molecular testing in this setting by determining whether IDH1 and TERT promoter (pTERT) mutations could be detected in nondiagnostic biopsies from glioma patients. METHODS: Using SNaPshot polymerase chain reaction, we retrospectively assessed IDH1 and pTERT mutation status in nondiagnostic biopsies from 28 glioma patients. RESULTS: The nondiagnostic biopsy (needle biopsy n = 25, open or endoscopic biopsy n = 3) consisted of slight glial cell hypercellularity, hemorrhage, and/or necrosis. After another biopsy (n = 23) or a subsequent surgical resection (n = 5) the diagnosis was an IDH1-wildtype (WT) pTERT-mutant glioma (glioblastoma n = 16, astrocytoma n = 4), an IDH1-mutant pTERT-mutant oligodendroglioma (n = 1), an IDH1-mutant pTERT-WT astrocytoma (n = 1), and an IDH1-WT pTERT-WT glioblastoma (n = 6). An IDH1 mutation was identified in the nondiagnostic biopsies of the 2 IDH-mutant gliomas, and a pTERT mutation in the nondiagnostic biopsies of 16 out of the 21 of pTERT mutant-gliomas (76%). Overall, an IDH1 and/or a pTERT mutation were detected in 17 out of 28 (61%) of nondiagnostic biopsies. Retrospective analysis of the nondiagnostic biopsies based on these results and on imaging characteristics suggested that a new biopsy could have been avoided in 6 patients in whom a diagnosis of "molecular glioblastoma" could have been done with a high level of confidence. CONCLUSION: In the present series, IDH1 and pTERT mutations could be detected in a high proportion of nondiagnostic biopsies from glioma patients. Molecular testing may facilitate the interpretation of nondiagnostic biopsies in patients with a suspected glioma.
BACKGROUND: Biopsies in patients with a suspected glioma are occasionally nondiagnostic. OBJECTIVE: To explore the utility of molecular testing in this setting by determining whether IDH1 and TERT promoter (pTERT) mutations could be detected in nondiagnostic biopsies from gliomapatients. METHODS: Using SNaPshot polymerase chain reaction, we retrospectively assessed IDH1 and pTERT mutation status in nondiagnostic biopsies from 28 gliomapatients. RESULTS: The nondiagnostic biopsy (needle biopsy n = 25, open or endoscopic biopsy n = 3) consisted of slight glial cell hypercellularity, hemorrhage, and/or necrosis. After another biopsy (n = 23) or a subsequent surgical resection (n = 5) the diagnosis was an IDH1-wildtype (WT) pTERT-mutant glioma (glioblastoma n = 16, astrocytoma n = 4), an IDH1-mutant pTERT-mutant oligodendroglioma (n = 1), an IDH1-mutant pTERT-WT astrocytoma (n = 1), and an IDH1-WT pTERT-WT glioblastoma (n = 6). An IDH1 mutation was identified in the nondiagnostic biopsies of the 2 IDH-mutant gliomas, and a pTERT mutation in the nondiagnostic biopsies of 16 out of the 21 of pTERT mutant-gliomas (76%). Overall, an IDH1 and/or a pTERT mutation were detected in 17 out of 28 (61%) of nondiagnostic biopsies. Retrospective analysis of the nondiagnostic biopsies based on these results and on imaging characteristics suggested that a new biopsy could have been avoided in 6 patients in whom a diagnosis of "molecular glioblastoma" could have been done with a high level of confidence. CONCLUSION: In the present series, IDH1 and pTERT mutations could be detected in a high proportion of nondiagnostic biopsies from gliomapatients. Molecular testing may facilitate the interpretation of nondiagnostic biopsies in patients with a suspected glioma.