Although it is known that oncogenic signaling caused by overexpression of genes such as PDGFRA is responsible for robust glioma growth and cell infiltration, the mechanisms underlying glioblastoma malignancy remain largely elusive.
No significant difference was observed in the frequency of amplification of these genes in primary and secondary glioblastomas or in glioblastomas with and without IDH1 mutations, suggesting that amplification of PDGFRA, KIT and KDR may be implicated in the pathogenesis of a small fraction of both subtypes of glioblastoma.
Phosphorylated receptor tyrosine kinase profiling showed a specific activation of platelet-derived growth factor receptor alpha/beta in EGFRvIII-transduced pediatric glioblastoma cells, and targeted coinhibition with erlotinib and imatinib leads to enhanced efficacy in this model.
We also detected amplifications of epidermal growth factor receptor (EGFR) or platelet-derived growth factor receptor alpha (PDGFRalpha) in a few of the 13 cases of glioblastoma multiforme analyzed.
Overexpression of PDGF system components, particularly the alpha subtype receptor (PDGFRA), is common in glial tumors, and PDGFRA gene amplification has been reported in glioblastomas.
The association of PDGFR-alpha expression with a distinct subset of glioblastomas characterized by loss of heterozygosity 17p further supports the differentiation of these tumors into molecular variants.
A common theme in glioblastoma is the amplification of genes that code for growth factor receptors of the protein-tyrosine kinase family (epidermal growth factor receptor, platelet-derived growth factor receptor-alpha, met).