CCR6 and renal cell carcinoma: We read with interest the paper by Suguru Kadomoto et al. entitled “Tumor-associated macrophages induce migration of renal cell carcinoma cells via activation of the CCL20-CCR6 axis”, published in Cancers [3], in which they report that the CCL20-CCR6 axis induces migration and epithelial–mesenchymal transition (EMT) of ACHN and Caki-1 RCC cells in co-cultures with THP-1/U937-derived tumor conditioned macrophages.