A Cytokine array of cell supernatant from THP-1 derived M2 macrophages co-cultured in different MDA-MB-231 CM as indicated (AAH-CYT-G3, RayBiotech, 42 human cytokines, part of the results was shown). B The IL-10 concentrations of cell supernatant from THP-1 derived M2 macrophages co-cultured in different MDA-MB-231 CM as indicated were analyzed by ELISA. C Transwell assay for MDA-MB-231 cells treated with EZH2 inhibitors were plated on the upper cell culture inserts, with culture medium alone (NC), or IL-4-activated THP-1 cells (M2 macrophages) plated in the lower chambers, in the presence or absence of an anti-IL10 antibody at 10 ng/ml, or an isotype-matched IgG control (IgG). D Transwell assay for MDA-MB-231 cells treated with EZH2 siRNAs were plated on the upper cell culture inserts, with culture medium alone (NC), or IL-4-activated THP-1 cells (M2 macrophages) plated in the lower chambers, in the presence or absence of IL-10 at 20 ng/ml. E MDA-MB-231 cells were treated with IL-10 at 20 ng/ml for 24 h, and subjected to human phospho-RTK array (R&D, ARY001B). Each kinase is spotted in duplicate. The pairs of dots in each corner (with the exception of the negative control pair at the lower left corner) are positive controls. The upregulated responding kinases were shown in red frame, with the name of the corresponding kinases. MDA-MB-231 cells were treated with or without 5 μM Gefitinib for 48 h before IL-10 stimulation as indicated for 24 h. The migration capacity was analyzed by transwell assay F and the phosphorylation of EGFR, Src and STAT3 and TGF-β level were tested by western blot G. H IHC staining of CD31 in the tumor tissue from EPZ-6438 or vehicle treated PDX6305 model and BT549 control or EZH2 sgRNA xenografts. Scale bar, 50 μm. The positive area of CD31 in IHC was quantified and the shown were representative of replicates. Statistical significance was addressed using unpaired, two‐tailed Student’s t‐test, *p < 0.05, **p < 0.01, ***p < 0.001, NS not significant. I Model describing that EZH2 in BC promotes tumor progression and metastasis by increasing CCL2-dependent recruitment and polarization of M2 TAMs, which reciprocally secrete IL-10, VEGF and other cytokines to activate EGFR signaling in cancer cells (the lung is created from BioRender.com).