1. Department of Pathology Asahikawa Medical University Asahikawa Japan
2. Department of Oral and Maxillofacial Surgery Asahikawa Medical University Asahikawa Japan
3. Respiratory and Breast Center Asahikawa Medical University Hospital Asahikawa Japan
4. Department of Otolaryngology, Head and Neck Surgery Asahikawa Medical University Asahikawa Japan