CCL5 and colorectal carcinoma: It has been reported that increased CCL5 secretion by tumor necrosis factor (TNF)-α stimulated MSCs and then MSCs promote CRC cell proliferation and progression can be accomplished by further activation of the epithelial-mesenchymal transition (EMT) process through the CCL5/CCR1/β-catenin/Slug pathway (69)(Figure 1).