[1] Department of Urology, Univ. TX M. D. Anderson Cancer Ctr., Houston, TX, United States
[2] Department of Pathology, Univ. TX M. D. Anderson Cancer Ctr., Houston, TX, United States
[3] Department of Biomathematics, Univ. TX M. D. Anderson Cancer Ctr., Houston, TX, United States
[4] Departments of Surgery and Oncology, Division of Urology, University of Western Ontario, London, Ont., Canada
[5] Department of Pathology, Long Island Jewish Medical Center, New Hyde Park, NY, United States
[6] Department of Urology, Univ. TX M. D. Anderson Cancer Ctr., Box 446, 1515 Holcombe Blvd., Houston, TX 77030, United States