1. The First School of Clinical Medicine, Lanzhou University, Lanzhou, Gansu 730000, P.R. China
2. Department of Oncology Surgery, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
3. Department of General Surgery, Baiyin First People's Hospital, Baiyin, Gansu 730900, P.R. China
4. Department of Endocrinology, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China
5. Department of Gastroenterology, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R. China