1Department of Gastroenterology and Hepatology, National Hospital Organization, Fukuyama Medical Center, Fukuyama, Hiroshima, Japan;

2Department of Laboratory and Pathology, National Hospital Organization, Fukuyama Medical Center, Fukuyama, Hiroshima, Japan;

3Department of Surgery, National Hospital Organization, Fukuyama Medical Center, Fukuyama, Hiroshima, Japan.

Correspondence: Masahiro Sakata, MD, PhD. E-mail: [email protected].