1. Department of Endoscopy, Respiratory Endoscopy Division, National Cancer Center Hospital, 5-1-1, Tsukiji Chou-ku, Tokyo, Japan
2. Department of Thoracic Oncology, National Cancer Center Hospital, 5-1-1, Tsukiji, Chuo-ku, Tokyo, Japan
3. Department of Respiratory Medicine, Tokyo Saiseikai Central Hospital, 1-4-17 Mita, Minato-ku, Tokyo, Japan
4. Department of Pathology and Clinical Laboratories, Pathology Division, National Cancer Center Hospital, 5-1-1, Tsukiji Chou-ku, Tokyo, Japan