Moonkyoo Kong1, Ji-Youn Sung2, Seung Hyeun Lee3. 1. Division of Lung/Head and Neck Oncology, Department of Radiation Oncology, Kyung Hee University Medical Center, Kyung Hee University School of Medicine, Seoul, Republic of Korea. 2. Department of Pathology, Kyung Hee University Medical Center, Kyung Hee University School of Medicine, Seoul, Republic of Korea. 3. Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Kyung Hee University Medical Center, Kyung Hee University School of Medicine, Seoul, Republic of Korea. Electronic address: humanmd04@hanmail.net.