[1] SIR Hosp, Dept Pathol, N-4068 Stavanger, Norway
[2] Free Univ Amsterdam, Med Ctr, Dept Epidemiol & Biostat, Amsterdam, Netherlands
[3] Gemini Hosp, Dept Urol, Den Helder, Netherlands
[4] Med Ctr Alkmaar, Dept Urol, Alkmaar, Netherlands
[5] Med Ctr Alkmaar, Dept Pathol, Alkmaar, Netherlands
[6] Free Univ Amsterdam, Dept Pathol, Amsterdam, Netherlands