PDGFRB and glioblastoma: Amplification or loss of regulation of several other molecular markers in addition to EGFR and PTEN involved in the PI3k pathway have been implicated in human glioblastoma: platelet-derived growth factor receptor (PDGFR), fibroblast growth factor receptor (FGFR), and other tyrosine kinase receptors [1], [12], [21].