1. Department of Medicine, Graduate School of Medicine, Pusan National University, Busan 602-739, Korea
2. Department of Obstetrics and Gynecology, Pusan National University School of Medicine, and Medical Research Institute and Pusan Cancer Center, Pusan National University Hospital, Busan 602-739, Korea
3. Department of Pathology, Pusan National University School of Medicine, and Medical Research Institute and Pusan Cancer Center, Pusan National University Hospital, Busan 602-739, Korea
4. Department of Physiology, College of Medicine, Pusan National University, Busan 602-739, Korea