1. Graduate School, Southwest Medical University, Luzhou, Sichuan 646000, China
2. Department of General Surgery, The Second Affiliated Hospital of Chengdu Medical College, China National Nuclear Corporation 416 Hospital, Chengdu, Sichuan 610051, China
3. The School of Biological Science and Technology, Chengdu Medical College, Chengdu 610083, China
4. Department of Gastrointestinal Surgery, Sichuan Academy of Medical Sciences and Sichuan Provincial People’s Hospital, Chengdu, Sichuan 610072, China