ARG1 and neoplasm: In contrast, M2-type macrophages are mainly induced by IL-4 and secrete anti-inflammatory factors such as CD206, Arg-1, and interleukin-10.[20] M2-type macrophages regulate the function of immune system, inhibit inflammation, and promote tumor formation.[21] In this study, Western blot, immunofluorescence and flow cytometry demonstrated that 24-h IL-4 treatment of macrophages resulted in an increase in the expression of M2-type polarization markers CD206 and Arg-1 compared with the control groups (Fig. 5).