The poorly differentiated component in endoscopic biopsy predicts submucosal invasion in superficial Barrett's esophageal adenocarcinoma. - Namikawa K; Fujisaki J; Ikenoyama Y; Tokai Y; Yoshimizu S; Horiuchi Y; Ishiyama A; Yoshio T; Hirasawa T; Watanabe M; Nakano K; Takamatsu M; et al. (Esophagus : official journal of the Japan Esophageal Society, 2026)