In contrast, M2 macrophages are capable of secreting cytokines that facilitate immunosuppressive and tumor‐promoting activities, such as TGF‐β, Arg‐1, Mrc1, IL‐10, etc.37, 38Here, we showed that KCND2 knockdown inhibited the M2 macrophages secretion of factors such as Arg1, Mrc1, IL‐6, IL‐10, and VEGF compared to controls in vivo, suggesting that KCND2 might potentially promote the growth of gastric cancer through activation of M2 macrophages. The gene discussed is MRC1; the disease is neoplasm.