Anatomical localization of isocitrate dehydrogenase 1 mutation: a voxel-based radiographic study of 146 low-grade gliomas

Background and purpose: A brain tumor's location is associated with the genetic profile of its tumor precursor cells. Mutations in isocitrate dehydrogenase 1 (IDH1) are an early event in tumor development and play a critical role in gliomagenesis. This study was conducted to specify the anatomical characteristics of IDH1 mutation in low-grade gliomas and to further explore the origin of gliomas with IDH1 mutation. The impact of IDH1 mutation on disease prognosis was also evaluated.

Methods: The pre-operative magnetic resonance images obtained from 146 patients with histologically confirmed low-grade glioma were analyzed retrospectively. All tumors were manually marked and registered to the standard location. Voxel-based lesion-symptom mapping analysis was used to identify brain regions associated with a high occurrence of IDH1 mutation. Progression-free survival and overall survival were estimated using the Kaplan-Meier method, and potential prognostic factors were evaluated using the multivariate proportional hazards model.

Results: Isocitrate dehydrogenase 1 mutated low-grade gliomas occurred most frequently in the frontal lobe, and specifically in the area surrounding the rostral extension of the lateral ventricles. Additionally, it was demonstrated that IDH1 mutation was an independent predictor for longer progression-free survival and overall survival.

Conclusions: Low-grade gliomas with IDH1 mutation are region-specific and preferentially located surrounding the rostral extension of the lateral ventricles. Furthermore, such mutations are associated with a favorable clinical outcome.