1. Department of Gastroenterology, Qilu Hospital, Shandong University, Jinan, China
2. Department of Pathology, the Second Affiliated Hospital, Shandong University, Jinan, China
3. I. Medical Clinic, University of Mainz, Mainz, Germany
4. State Key Laboratory of Cancer Biology and Xijing Hospital of Digestive Diseases, Fourth Military Medical University, Xi'an, China