[1] Prov Inst Hyg, B-2000 Antwerp 1, Belgium
[2] Gen Cent Hosp Lab, Antwerp, Belgium
[3] Middelheim Hosp, Dept Pathol, Antwerp, Belgium
[4] Erasmus Univ, Med Ctr, Rotterdam, Netherlands
[5] Comprehens Canc Ctr S, Eindhoven, Netherlands
[6] Ctr Oncol, Antwerp, Belgium