CCR5 and colonic neoplasm: Despite this obviously beneficial role of CCL4 for the immunological control of CRC disease, it cannot be neglected that colon tumor-infiltrating regulatory T cells (Treg cells) could be characterized by significantly increased expression of the CCL4 receptor CCR5 compared to tumor-infiltrating conventional T cells but also in comparison to Treg cells located in the mucosa of the distal colon [47].