In order to verify that it is TIMP‐2 rather than other cytokines that mainly caused the resistance of CRC cells to 5‐Fu, we added recombinant TIMP‐2 to the culture medium of non‐resistant cell lines and added neutralising TIMP‐2 antibodies to the culture medium of drug‐resistant cell lines respectively. This evidence concerns the gene TIMP2 and colorectal carcinoma.