1. Department of Pancreatic Surgery, Fudan University, Shanghai Cancer Center, Shanghai 20032, P.R. China
2. Pancreatic Cancer Institute, Fudan University, Shanghai 200032, P.R. China
3. Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P.R. China
4. Department of Pancreatic Surgery, Huashan Hospital, Shanghai 200040, P.R. China
5. Department of Medicine, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
6. Department of Surgery, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA