1. Department of Integrated Diagnostic Pathology, Nippon Medical School, Tokyo 113-8602, Japan
2. Division of Pathology, Cancer Institute, Japanese Foundation for Cancer Research, Tokyo 135-8550, Japan
3. Department of Endocrine Surgery, Nippon Medical School Hospital, Tokyo 113-8603, Japan
4. Division of Head and Neck, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo 135-8550, Japan