MTOR and chordoma: It has been reported that various receptor tyrosine kinases are expressed in chordoma [14,15], including PDGFR-a/b, KIT, HER2, EGFR, VEGFR, and c-MET, etc., which activates downstream MAP kinase, PI3K/AKT/mTOR, and STAT3 signaling, etc. Recently, new insights into the molecular mechanisms of chordomas have led to the identification of novel potential treatments.