Epidemiology of brain tumors.

摘要: Gliomas account for more than 70% of all brain tumors, and these, glioblastoma is the most frequent malignant histologic type (World Health Organization [WHO] grade IV). There a tendency toward higher incidence gliomas in highly developed, industrialized countries. Some reports indicate that Caucasians have African or Asian populations. With exception pilocytic astrocytomas (WHO I), prognosis glioma patients still poor. Fewer 3% are alive at 5 years after diagnosis, older age being significant consistent prognostic factor poorer outcome. components several inherited tumor syndromes, but prevalence these syndromes very low. Many environmental lifestyle factors including occupations, carcinogens, diet been reported to be associated with an elevated risk, only unequivocally increased risk therapeutic X-irradiation. In particular, children treated X-irradiation acute lymphoblastic leukemia show significantly developing primitive neuroectodermal often within 10 therapy. Significant correlation between G:C --> A:T transitions TP53 gene promoter methylation O6 -methylguanine-DNA methyltransferase (MGMT) glio-mas studies, suggesting possible involvement O6-methylguanine DNA adducts, which may produced by exogenous endogenous alkylating agents development gliomas.