The present invention provides a TOP2A inhibition by temozolomide useful for predicting glioblastoma patient's survival. Glioblastoma (GBM) is the most common, malignant primary adult brain tumor. The conventional treatments for GBM, include surgery, radiation, and chemotherapy which have only modestly improved patient survival. The patients with GBM expressing higher TOP2A transcript levels had better prognosis. More interestingly, the present invention reports that temozolomide is an inhibitor of TOP2A activity