1. Department of Urology, Northwestern University Feinberg School of Medicine, Tarry Building, Room 16-733, 303 East Chicago Avenue, Chicago, IL 60611, USA
2. Department of Urology, University of California at Irvine, Medical Center, Orange, CA 92868, USA
3. Department of Pathology and Laboratory Medicine, University of California at Irvine, Medical Surgery Building I, Room 168, Irvine, CA 92697, USA
4. Department of Surgery, NorthShore University HealthSystem, Evanston, IL 60201, USA
5. Department of Statistics, University of Akron, Akron, OH 44325, USA
6. Department of Family and Community Medicine, Northeast Ohio Medical University, Rootstown, OH 44272, USA