Moreover, the integrin αvβ6-mediated TGF-β activation can further stimulate fibroblasts to secrete stromal cell-derived factor-1 (SDF-1), resulting in CRC invasion via the SDF-1/C-X-C chemokine receptor type 4 (CXCR4) axis (Peng et al., 2018). Here, CXCR4 is linked to colorectal carcinoma.