1. Endoscopy Division, National Cancer Center Hospital, Tokyo, Japan
2. Biostatistics Division, Center for Research Administration and Support, National Cancer Center, Tokyo Japan
3. Esophageal Surgery Division, National Cancer Center Hospital, Tokyo, Japan.
4. Division of Pathology and Clinical Laboratories, National Cancer Center Hospital, Tokyo, Japan
5. Division of Molecular Pathology, National Cancer Center Research Institute, Tokyo, Japan