RETN and neoplasm: Our results indicate that TLR4 is widely expressed in NPC as well as in head and neck tumors; that its expression level is positively correlated with high grades of tumor and lymph node metastasis in HNSC; that the inhibition of TLR4 signaling prevents resistin-induced migration and invasion; and that TLR4 knockdown prevents the resistin-induced expression of multiple critical EMT proteins.