They are induced by IL-4 or IL-4 and IL-13, secrete IL-10, IL-1 receptor antagonists (IL-1RA) and a variety of chemokines, and highly express arginase, mannose receptor, scavenger receptor, etc. M2 macrophages display a low ability to present antigens, mainly induce Th2 type immune responses, and are mainly involved in cell growth, angiogenesis, immunosuppression, tissue repair, and interstitial formation 23, 24, thereby promoting tumor growth. The gene discussed is IL4; the disease is neoplasm.