Because macrophages interplay with tumor cells to produce a large amount of CCL20 in the co-culture, and the selective depletion of macrophages completely disrupted the release of CCL20 not only by TAMs but also mouse CRC cells in CD11b-DTR mice, we conclude that TAMs significantly contribute to the production of CCL20 which drives CCR6+ Treg-cell recruitment to the tumor tissue. This evidence concerns the gene ITGAM and colorectal carcinoma.