1Department of Gastrointestinal Oncology, Osaka International Cancer Institute, Osaka, Japan;

2Department of Diagnostic Pathology and Cytology, Osaka International Cancer Institute, Osaka, Japan;

3Department of Gastroenterology, Nara Prefecture Seiwa Medical Center, Nara, Japan;

4Department of Gastroenterology and Hepatology, Gunma University Graduate School of Medicine, Maebashi, Japan.

Correspondence: Minoru Kato, MD, PhD. E-mail: [email protected].