1. Department of Biological Sciences, College of Natural Sciences, Seoul National University, Gwanak-gu, Seoul, 151-747, South Korea
2. Department of Pathology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seocho-Gu, Seoul, 133-782, South Korea
3. Department of Pathology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, 152-703, South Korea