1. Department of Urology Surgery, The Third Affiliated Hospital, College of Clinical Medicine of Henan University of Science and Technology, Luoyang, Henan 471003, P.R. China
2. Department of Urology Surgery, The First Affiliated Hospital, College of Clinical Medicine of Henan University of Science and Technology, Luoyang, Henan 471003, P.R. China
3. Department of Pancreatic Cancer, Tianjin Medical University Cancer Institute and Hospital, Key Laboratory of Cancer Prevention and Therapy, National Clinical Research Center for Cancer, Tianjin 300060, P.R. China