1. Department of Internal Medicine, Endocrine Research Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
2. Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Surgery, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Pathology, Yonsei University College of Medicine, Seoul, Korea.