1. Division of Head and Neck Surgery, Shizuoka Cancer Center, Sunto-gun, Japan
2. Department of Otolaryngology, Head and Neck Surgery, Ehime University School of Medicine, Toon, Japan
3. Division of Hematology and Stem Cell Transplantation, Shizuoka Cancer Center, Sunto-gun, Japan
4. Division of Pathology, Shizuoka Cancer Center, Sunto-gun, Japan