1. Department of Gastroenterology Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong 250117, P.R. China
2. Department of Clinical Oncology, Taian City Central Hospital, Taian, Shandong 271000, P.R. China
3. Department of Oncology, Xiamen Changgung Hospital, Xiamen, Fujian 361000, P.R. China