The proliferation and metastasis of tumor cells can be promoted by M2 macrophages by releasing anti-inflammatory factors such as IL-10 and TGF-β [38], immunosuppressive factors such as PGE2, arginase-I [39], somatomedins such as EGF, CCL18, and HIF-1α [40] and pro-metastasis factors such as MMPs, uPA, and uPAR [41]. This evidence concerns the gene CCL18 and neoplasm.