1. Department of Internal Medicine, Saga Medical School, Saga University, Saga 849‑8501, Japan
2. Department of Gastroenterology and Hepatology, Hokkaido University Graduate School of Medicine, Department of Gastroenterology and Hepatology, Graduate School of Medicine, Hokkaido University, Sapporo, Hokkaido 060‑8638, Japan
3. Department of Tumor Virology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700‑8558, Japan