1. Department of Urology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuou-ku, Chiba 260-8670, Japan
2. Division of Urology, Chiba Cancer Center, Chiba 260-8717, Japan
3. Department of Urology, Toho University Sakura Medical Center, Sakura 285-8741, Japan
4. Department of Pathology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan