1. Department of Anatomic Pathology; Graduate School of Medical Sciences; Kyushu University; Fukuoka; Japan
2. Department of Otolaryngology; Graduate School of Medical Sciences; Kyushu University; Fukuoka; Japan
3. Department of Pathology; National Kyushu Cancer Center; Fukuoka; Japan
4. Department of Head and Neck Surgery; National Kyushu Cancer Center; Fukuoka; Japan