Tumors of the central nervous system (CNS) are common causes of morbidity and 
mortality. These tumors can occur sporadically or in individuals with genetic 
disorders predisposing to cancer development. Such syndromes include 
neurofibromatosis type 2, neurofibromatosis type 1, Li-Fraumeni syndrome, as 
well as von Hippel-Lindau disease, tuberous sclerosis, and Turcot syndrome. 
There may also be familial syndromes resulting in glioma or meningioma alone, 
but these are not well understood. Development of sporadic gliomas is 
accompanied by a number of molecular genetic alterations, including activation 
of dominant oncogenes and inactivation of tumor suppressor genes. Some of these 
alterations may be associated with progression of gliomas to their most 
malignant form, glioblastoma multiforme. However, at this time molecular genetic 
analysis of gliomas does not provide better prognosis than histopathological 
staging. Recently, experimental treatments of gliomas in rodents, using gene 
therapy, have been reported. Results of these studies have been promising, and 
these techniques may represent a future direction for therapy in humans.