EGFR and head and neck squamous cell carcinoma: In head and neck squamous cell carcinomas (HNSCCs), the extracellular domain of EpCAM (EpEX) has a role of a ligand of EGFR that induces EGFR-dependent proliferation but counteracts EGF-induced EMT.90 On the contrary, the overexpression of EpCAM could promote EMT and stemness and metastasis through PTEN/AKT/mTOR signal pathway in NPC cells.91 Li et al. found that EphA2 is associated with the formation of NPC as a tumor promoter.