Reliability of noncontrast-enhancing tumor as a biomarker of IDH1 mutation status in glioblastoma.
Isocitrate dehydrogenase 1 (IDH1) mutations in gliomas have been associated with a frontal lobe location and a greater proportion of noncontrast-enhancing tumour (nCET). The purpose of our study was to validate the utility of MRI imaging features in predicting IDH1 mutations in glioblastomas. Pre-operative MRIs of new glioblastoma patients, consisting of at least FLAIR and T1-weighted post-contrast sequences, were reviewed by a neuroradiologist based primarily on the VASARI feature set. IDH1 mutation testing was performed on all patients using immunohistochemistry. 153 patients met the inclusion criteria, of whom five had IDH1 mutations (3.3%). A frontal lobe location had equivalent frequency in both the IDH1-mutated and IDH1-wildtype cohorts (p=1.000). Three (60%) of the IDH1-mutated tumours had >33% nCET, compared to 21% of IDH1-wildtype (p=0.073). 12 tumours had a frontal lobe epicentre and >33% nCET, all being IDH1-wildtype. All five IDH1-mutated tumours had either a frontal lobe epicentre or >33% nCET, but none had both these features. Our results question the strength of the association between frontal lobe glioblastomas with substantial nCET and IDH1 mutations, as these features are also relatively frequent in IDH1-wildtype tumours, which are much more common. MRI is thus more useful for ruling out an IDH1 mutation rather than strongly suggesting its presence: if a particular glioblastoma does not have a frontal lobe epicentre and has less than 33% nCET, it can be predicted to be IDH1-wildtype with a high degree of confidence.
['Lasocki|Arian|A|', 'Tsui|Alpha|A|', 'Gaillard|Frank|F|', 'Tacey|Mark|M|', 'Drummond|Katharine|K|', 'Stuckey|Stephen|S|']
D000328:Adult D015415:Biomarkers D014408:Biomarkers, Tumor D001932:Brain Neoplasms D005260:Female D005909:Glioblastoma D006801:Humans D007521:Isocitrate Dehydrogenase D008279:Magnetic Resonance Imaging D008297:Male D008875:Middle Aged D009154:Mutation D015203:Reproducibility of Results
Glioblastoma Isocitrate dehydrogenase Noncontrast-enhancing tumour Magnetic Resonance Imaging