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Glioblastoma multiforme (GBM) formation is either de novo (primary GBMs) or due to the progression of a lower grade glioma to a higher grade one through the acquisition of additional mutations (secondary GBMs). In primary GBM, disruption of the p53 pathway often occurs through loss of ARF, or less frequently through amplification of MDM2. Disruption of the RB pathway occurs through loss of INK4A. Amplification and/or mutation of the epidermal growth factor receptor (EGFR) is the most frequently detected genetic defect that is associated with primary GBM. In secondary GBM, loss of p53 and activation of the growth-factor–receptor-tyrosine-kinase signalling pathway (such as through overexpression of PDGF/PDGFR ) initiates tumour formation,whereas disruption of the retinoblastoma (RB) pathway contributes to the progression of tumour development. Loss of PTEN has been implicated in both pathways, although it is much more common in the pathogenesis of primary GBM. |
Glioma - Reference pathway (KO)
