miR-18a from M2 macrophages influencing TGF signaling pathway in NPC cells was determined by Western blot assay through testing TGF signaling pathway-related proteins in SUNE-1 cells and CNE2 cells which had co-cultured with miR-18a mimics-, miR-18a inhibitors-, si-TGFBR3-, or OE-TGFBR3-transfected M2 macrophages in the Transwell chamber. The gene discussed is TGFBR3; the disease is nasopharyngeal carcinoma.