1 Department of Gastroenterology and Hepatology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan.
2 Department of Oncology and Laboratory Medicine, Graduate School of Medicine, Yamaguchi University, Ube, Yamaguchi, Japan.
3 Department of Gastroenterology and Hepatology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi, 755-8505, Japan. t-takami@yamaguchi-u.ac.jp.