1. Departments of Otolaryngology; Asan Medical Center; University of Ulsan College of Medicine; Seoul Republic of Korea
2. Clinical Epidemiology and Biostatistics; Asan Medical Center; University of Ulsan College of Medicine; Seoul Republic of Korea
3. Pathology; Asan Medical Center; University of Ulsan College of Medicine; Seoul Republic of Korea
4. Biomedical Research Institute; Korea Institute of Science and Technology; Seoul Republic of Korea