Optimal number of endoscopic biopsies for diagnosis of early gastric cancer oleh Masaki Nishitani, Naohiro Yoshida, Shigetsugu Tsuji, Teppei Masunaga, Hirokazu Hirai, Saori Miyajima, Akihiro Dejima, Takashi Nakashima, Shigenori Wakita, Kenichi Takemura, Hiroshi Minato, Shuichi Kaneko, Hisashi Doyama