MS2 BRAIN TUMORS AND EPILEPSY

A brain tumor is one of the major causes of epilepsy, and glioma patients frequently exhibit seizures. Epileptic seizure, one of the features of glioma, is also known to be correlated with better outcome of patients. One of the reasons why patients with seizures have a good prognosis is that oligodendroglial tumors tends to cause epilepsy. However, even if limited to glioblastomas, the prognosis with epilepsy is still better than the others. Recently, the association between IDH mutations and epilepsy had been reported. IDH is an enzyme which converts isocitrate to alpha-ketoglutarate, but when this enzyme is mutated, 2-hydroxyglutarate (2HG) is produced instead of alpha-ketoglutarate. The molecular structure of 2HG is similar to glutamate, and it had been also reported that 2HG binds to the NMDA receptor. Indeed, in our cases, the IDH-mutation rate was higher in cases with epilepsy than the others. From our study of gene expression profiles, it was also clarified that the expressions of neuron-related genes were higher in cases with epileptic seizures, suggesting that many tumors classified as pro-neural type were included in this subset. As described, epilepsy phenotype is important, even in daily practice, because it predict the molecular status of gliomas and estimates the prognosis of the patients. On the other hand, control of the seizures is important to keep patients’ QoL and to provide effective treatment. In this seminar, the control of epilepsy during and early after surgery, and how to manage status epilepticus will be reviewed.