1. Samsung Biomedical Research Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea.
2. Division of Biological Science and Technology, Yonsei University, Wonju 220-710, Korea.
3. Department of Obstetrics and Gynecology, Chung-Ang University School of Medicine, Seoul 156-755, Korea.
4. Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea.
5. Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 135-710, Korea.