IL10 and neoplasm: We found that the expression level of pro-tumor cytokines including TGF-β, IL-10 and VEGF were significantly higher in TANs comparing to those in neutrophils in the peripheral blood of both non-tumor-bearing mice and C666-1 tumor-bearing mice, which confirmed that TANs in NPC tumors have pro-tumorigenic properties (Figures 5C,D).