In order to improve the therapeutic efficacy of 5FU and elucidate the mechanism underlying the development of 5FU resistance in patients with CRC, we firstly identified glutamine (Gln) as an important amino acid to induce resistance to 5FU-triggered tumor suppression of CRC-PC via activating mTOR pathway using metabolomics analysis. The gene discussed is MTOR; the disease is colorectal carcinoma.