1. The Second Affiliated Hospital, Chongqing Medical University; Department of Hepatobiliary Surgery; Chongqing China
2. University of Padova; Department of Surgery, Oncology and Gastroenterology; Padova Italy
3. Jiangjin Central Hospital; Department of Clinical Laboratory; No. 65, Jiang Zhou Road Chongqing China 402260
4. West China Hospital, Sichuan University; Department of Bile Duct Surgery; No. 37, Guo Xue Xiang Chengdu Sichuan China 610041
5. McMaster University; Department of Medicine, Division of Gastroenterology; 1280 Main Street West Room HSC 3N51 Hamilton ON Canada L8S 4K1
6. University of Padova; Meta-Analysis Unit, Department of Surgery, Oncology and Gastroenterology; via Giustiniani 2 Padova Italy 35128