Multiple soluble tumor-derived products, such as the chemokines CCL2, CCL5 and the cytokines IL10 and TGFβ, etc., recruit tumor-associated macrophages (TAMs) (3–6) and myeloid-derived suppressor cells (MDSCs) (7) into the TME, and lead to the impairment of differentiation, maturation and function of dendritic cells (DCs) (8, 9). The gene discussed is CCL2; the disease is neoplasm.