Department of Hepatobiliary and Pancreatic Oncology, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan

Yuya Hisada, Susumu Hijioka, Go Ikeda, Kosuke Maehara, Hidetoshi Kitamura, Shota Harai, Motohiro Yoshinari, Yuki Kawasaki, Yumi Murashima, Takehiko Koga, Kotaro Takeshita, Yuta Maruki, Akihiro Ohba, Yoshikuni Nagashio, Shunsuke Kondo, Chigusa Morizane, Hideki Ueno & Takuji Okusaka

Department of Diagnostic Pathology, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan

Taiki Hashimoto & Yasushi Yatabe

Endoscopy Division, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, 104-0045, Japan

Yutaka Saito

Substantial contributions to the conception or design of the work, or acquisition, analysis or interpretation of data for the work: YH, SHi, GI, KM, TH, HK, SHa, MY, YK, YM, TK, KT, YM, AO, YN, SK, CM, HU, YS, YY, and TO; drafting the work or revising it critically for important intellectual content: YH, SHi, GI, KM, TH, HK, SHa, MY, YK, YM, TK, KT, YM, AO, YN, SK, CM, HU, YS, YY, and TO; final approval of the version to be published: YH, SHi, GI, KM, TH, HK, SHa, MY, YK, YM, TK, KT, YM, AO, YN, SK, CM, HU, YS, YY, and TO; agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved: YH, SHi, GI, KM, TH, HK, SHa, MY, YK, YM, TK, KT, YM, AO, YN, SK, CM, HU, YS, YY, and TO.

Correspondence to Susumu Hijioka.