1. Division of Colorectal Surgery; National Cancer Center Hospital East; Kashiwa Chiba 277-8577 Japan
2. Department of Surgery; Keio University School of Medicine; Shinjuku-Ku Tokyo 160-8582 Japan
3. Division of Pathology; Research Center for Innovative Oncology, National Cancer Center Hospital East; Kashiwa Chiba 277-8577 Japan
4. Laboratory of Cancer Biology, Department of Integrated Biosciences, Graduate School of Frontier Sciences; The University of Tokyo; Kashiwa Chiba 277-8561 Japan