CCL17 and malignant colon neoplasm: All these cells have been reported in colon cancer and can affect Treg cell dynamics; for example, pDCs and cDCs can promote the induction and expansion of Tregs; macrophages, depending on their polarization state (M2 or M1), can either enhance or suppress Treg activity, respectively, and neutrophils, can recruit Tregs into tumors through CCL17 [66–68].