Department of Gastroenterology and Hepatology;
Graduate School of Medicine and Faculty of Medicine;
Hokkaido University;
Sapporo;
Hokkaido 060-0808;
Japan;
of Endoscopy;
Hokkaido University Hospital;
Sapporo;
Hokkaido 060-8648;
Japan;
Department of Cancer Pathology;
Hokkaido University Graduate School of Medicine;
Sapporo;
Hokkaido 060-0808;
Japan;
Department of Gastroenterology;
Hokkaido University Hospital;
Sapporo;
Hokkaido 060-8648;
Japan;
Department of Gastroenterology and Hepatology;
Hakodate Municipal Hospital;
Hakodate;
Hokkaido 041-8680;
Japan;
Human papillomavirus; Esophageal squamous cell carcinoma; Early esophageal cancer; Alcohol dehydrogenase-1B; Aldehyde dehydrogenase-2; Endoscopic resection;