CD9 and colorectal carcinoma: Through the use of these three CRC Colo-320 cell lines, our results have established: (i) that the interaction between integrin α5β1 −expressed on CRC cells or on PMCs− and its novel ligand Dis-ADAM17 −exposed on exosomes− mediates the binding and uptake of exosomes produced by CRC Colo-320 cells; and (ii) that this process is negatively regulated by the expression of tetraspanin CD9 on the surface of exosomes.