Title Search [OP 1-1] Clinical and molecular characteristics of pathologic subtype in cholangiocarcinoma Keun Soo AHN (Keimyung University, Korea) [OP 1-2] Clinicopathological differences of HER2 protein expression in T2 gallbaldder cancer Byeong Gwan NOH (Pusan National University, Korea) [OP 1-3] Is the dissection of lymph nodes on the posterior surface of the head of the pancreas necessary for prognosis in gallbladder cancer? Hye Yeon YANG (Yonsei University, Korea) [OP 1-4] Can neuroendocrine carcinoma, intraductal mucinous papillary mucinous carcinoma, and pancreatic ductal adenocarcinoma be classified into the same categorical carcinoma? Ye Won JEON (University of Ulsan, Korea) [OP 1-5] T-tube drainage versus primary ductal closure following choledochotomy in a tertiary hospital: An open label randomized controlled trial Al Bryndon CASTILLO (Baguio General Hospital and Medical Center, Philippines) [OP 1-6] Survival outcome of R1 hilar resection cannot overcome survival of R0 pancreaticoduodenectomy even considering complication rate or adjuvant treatment in mid bile duct cancer Soo Yeun LIM (Sungkyunkwan University, Korea) [OP 1-7] Prognostic significance of HER2 expression in advanced gallbladder cancer Hee Ju SOHN (Chung-Ang University, Korea) [OP 1-8] The significance of vascular combined resection and reconstruction for locally advanced perihilar cholangiocarcinoma Ryusei MATSUYAMA (Yokohama City University, Japan)