[1] Yokohama City Univ, Div Endoscopy, Med Ctr, 4-57 Urafune Cho,Minami Ku, Yokohama, Kanagawa 2320024, Japan
[2] Yokohama City Univ, Inflammatory Bowel Dis Ctr, Med Ctr, Yokohama, Kanagawa, Japan
[3] Yokohama City Univ, Div Diagnost Pathol, Med Ctr, Yokohama, Kanagawa, Japan
[4] Yokohama City Univ, Dept Biostat, Grad Sch Med, Yokohama, Kanagawa, Japan
[5] Yokohama City Univ, Dept Gastroenterol, Grad Sch Med, Yokohama, Kanagawa, Japan