CD80 and neoplasm: On the other hand, when we co-cultured CQ-treated B16 or H22 tumor cells with macrophages, we found that CQ-treated tumor cells had minor effect on CD80 and CD86 expression, slightly upregulated MHC-II expression, but strikingly upregulated Arg1 and IL-10 expression (Supplementary Fig. 4g), suggesting that CQ-effected tumor cells do not contribute to M1 macrophage polarization.