Aberrant neuronal differentiation is common in glioma but is associated neither with epileptic seizures nor with better survival.

The mechanisms of glioma-associated seizures (GAS) have yet to be fully elucidated. Proneural subtype, isocitrate dehydrogenase 1 (IDH1) mutations, and epileptic seizures are closely associated suggesting that aberrant neuronal differentiation contributes to glioma-associated seizures. In a population-based cohort (n = 236), lack of stem cell marker expression (nestin, musashi) was significantly associated with IDH1 mutations and GAS at diagnosis.

High expression of cystine-glutamate antiporter xCT (SLC7A11) is an independent biomarker for epileptic seizures at diagnosis in glioma.

Epileptic seizures are an important cause of morbidity in glioma patients. Substantial lines of evidence support the concept of the excitatory neurotransmitter glutamate being a crucial mediator of glioma-associated seizures. In gliomas, non-vesicular secretion of glutamate via the cystine-glutamate exchanger (SLC7A11, xCT) constitutes the main mechanism contributing to high extracellular glutamate concentrations.