1. Department of Internal Medicine, Division of Medical Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-Gu, Seoul 120–752, Korea
2. Department of Pathology, Yonsei University College of Medicine, Seoul, Korea
3. Department of Hematology–Oncology, National University Cancer Institute, National University Health System, Singapore
4. Cancer Science Institute of Singapore, National University of Singapore, Singapore
5. Department of Internal Medicine, Division of Medical Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-Gu, Seoul 120–752, Korea. .