1. Department of Gastroenterological Surgery Yokohama City University School of Medicine Yokohama Japan
2. Department of Biostatistics Yokohama City University School of Medicine Yokohama Japan
3. Department of Radiation Oncology Yokohama City University School of Medicine Yokohama Japan
4. Department of Pathology Yokohama City University Hospital Yokohama Japan
5. Department of Molecular Pathology Yokohama City University School of Medicine Yokohama Japan