CCR5 and neoplasm: Most of the CD8+ CTL and type-1 helper T cells (Th1) at the invasion front of CRC tissues express CCR5, and expression of its ligand CCL5 in the tumor microenvironment is observed predominantly in the stromal CD8+ T lymphocytes at the invasion front [24], which may accelerate anti-tumor immunity in an autocrine and/or paracrine manner.