Ki-67 overexpression in WHO grade II gliomas is associated with poor postoperative seizure control

PURPOSE Seizures are the most common initial symptom in patients with low-grade gliomas, and approximately 30% of these patients still suffer from epilepsy after gross-total resection of the tumour. We examined the relationship between the overexpression of ki-67 in WHO grade II gliomas and seizure control. METHODS A series of 93 histologically confirmed WHO grade II glioma tissues were analysed through immunohistochemical staining for ki-67 expression. Follow-up visits regarding seizure control were scheduled at 12 months. The Engel classification was used to categorise patients' seizure status. RESULTS Of the 93 patients analysed, 65 (66.3%) patients initially presented with seizures. A total of 36 patients were diagnosed with WHO grade II oligodendrogliomas, 29 patients had oligoastrocytomas and 28 patients had astrocytomas. Ki-67 was over-expressed in 15 patients. One year after surgery poor seizure control was observed in 11 of these patients. In contrast, low ki-67 expression (<10%) was found in 78 patients. Poor seizure control was observed in 36 patients (difference between ki-67 over- and low expression groups P = 0.002). Logistic regression analysis revealed that patients with gross-total resection achieved better seizure control while ki-67 overexpression and age below 38 years were poor seizure control factors explained of the variance of seizure outcome (OR: 0.382, 4.354 and 1.822, respectively). CONCLUSIONS In WHO grade II gliomas, Ki-67 is a molecular marker which predicts poor seizure control of glioma patients after the resection of the tumour. Gross-total resection, ki-67 overexpression and age below 38 years significantly affect seizure prognosis.