MTOR and chondrosarcoma: Several signaling pathways, such as hedgehog, non-receptor tyrosine kinase (Src), phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/serine/threonine-protein kinase (AKT)/mammalian target of rapamycin (mTOR), and angiogenesis are suggested to play an important role in chondrosarcoma (6).