Glial tumors: the current state of scientific knowledge.

INTRODUCTION Glial tumors are the most common primary brain tumors. They are derived from astrocytes, oligodendroglial cells, and ependyma. The majority of glial tumors are malignant, and the median survival of patients with glioblastoma is between 12 and 24 months. Improvement in the outcome of patients will depend on a better understanding of the scientific basis of gliomagenesis and the translation of such knowledge to the clinical setting.