Gliomas are the most frequent primary brain tumors. They are derived from glial cells of astrocytic, oligodendroglial and ependymal origin. According to the WHO classification of brain tumors gliomas are divided in low-grade (grades I and II) and high-grade (grades III and IV) tumors. Low-grade tumors are well-differentiated, slow-growing lesions. Grade I tumors are well-circumscribed and often...
