1. Department of Pharmacology, Seoul National University College of Medicine, Seoul 110-799, Korea.
2. Cancer Research Institute, Department of Tumor Biology, Seoul National University College of Medicine, Seoul 110-746, Korea.
3. College of Pharmacy and Research Center for Bioresource and Health, Chungbuk National University, Cheongju 361-763, Korea.
4. Department of Anatomy, Seoul National University College of Medicine, Seoul 110-799, Korea.