1. Department of Urology, Ruhr-University Bochum, Bochum, Germany and Marienhospital Herne, Herne, Germany
2. Department of Epidemiology and Biostatistics, George Washington University, Washington, D.C
3. Department of Pathology, Ruhr-University Bochum, Bochum, Germany and Marienhospital Herne, Herne, Germany