MET and chordoma: With chordoma in particular, platelet-derived growth factor (PDGF) receptor (PDGFR), epidermal growth factor (EGF) receptor (EGFR) and hepatocyte growth factor (HGF) receptor (c-Met) are three RTKs thought to play a role in pathogenesis and malignant potential, as each has been shown to be overexpressed in chordoma [41,42].