In fact, it is widely accepted that the sequential accumulation of mutations that activate oncogenes and disrupt tumour suppressor genes, combined with multiple cycles of clonal. Less than 3 % of glioblastoma patients are still alive at 5 years after diagnosis, higher age being the most significant predictor of poor outcome. CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Cancer is a complex disease, with multiple genes in diverse pathways involved in its initiation, progression, invasion and metastasis. With the exception of pilocytic astrocytomas, the prognosis of glioma patients is still poor. The most common (65%) and most malignant type is glioblastoma. Clinics and pathology Etiology Gliomas account for>70 % of all primary brain tumors. Relevant features in the present section will concern GLIOMAS, tumors that are thought to be of glial cell origin. For simplicity, CNS tumors may be classified as GLIOMAS or NONGLIOMAS (see Table 1 which provides a summary of 2007 World Health Organization (WHO) classification). Classification Note Primary CNS tumors constitute a spectrum of pathological entities each with a distinct natural history that reflects the sequential accumulation of genetic lesions and the deregulation of growth-factor signalling pathways during neoplastic transformation.
