MTOR and head and neck squamous cell carcinoma: Previous stdies have shown that CCR7 can promote HNSCC metastasis and invasion through the Phoshatidylinositol 3 kinase (PI3K)/AKT/mTOR, Phospholipase C (PLC)/ Protein kinase B (PKC), Mitogen-activated protein kinase (MAPK) family, pyk2 and several other molecules [34,47,48].