1. Department of Neurosurgery, Brain Research Institute, Niigata University, Niigata, Japan
2. Department of Pathology, Brain Research Institute, Niigata University, Niigata, Japan
3. Department of Hematology, Endocrinology and Metabolism, Niigata University Faculty of Medicine, Niigata, Japan
4. Department of Neurosurgery, Kanazawa Medical University, Ishikawa, Japan
5. Department of Hematology and Immunology, Kanazawa Medical University, Ishikawa, Japan