[1] Japanese Fdn Canc Res, Dept Gastroenterol, Canc Inst Hosp, Tokyo, Japan
[2] Natl Canc Ctr, Endoscopy Div, Tokyo, Japan
[3] Tokyo Endoscop Clin, Tokyo, Japan
[4] Showa Univ, Digest Dis Ctr, Northern Yokohama Hosp, Yokohama, Kanagawa, Japan
[5] Hiroshima Univ Hosp, Dept Endoscopy, Hiroshima, Japan
[6] Japanese Fdn Canc Res, Dept Gastroenterol, Canc Inst Hosp, 3-8-31 Ariake,Koto Ku, Tokyo 1358550, Japan