1. The Key Laboratory of the Digestive System Tumors of Gansu Province, Department of Tumor Center, Lanzhou University Second Hospital, Lanzhou 730030, P. R. China
2. Institute of Biochemistry and Molecular Biology, School of Life Sciences, State Key Laboratory of Applied Organic Chemistry, Key Lab of Preclinical Study for New Drugs of Gansu Province, Lanzhou University, Lanzhou 730000, P. R. China