Chromosomal numerical aberrations of exfoliated cells in the urine detected by fluorescence in situ hybridization: clinical implication for the detection of bladder cancer

Numerical aberrations of chromosomes 7 and 9 of exfoliated cells from the urinary tract were examined using fluorescence in situ hybridization (FISH). To minimize contamination with inflammatory, squamous and normal transitional cells all samples were stained using Giemsa's solution and clusters of transitional cells were selected for FISH analysis. Samples collected from 21 patients who had cystoscopic monitoring for bladder cancer were used in this study. Cystoscopy was positive in seven patients and five biopsy-proven transitional cell carcinomas were identified. Among the patients with cancer recurrence, numerical chromosomal aberrations were detected in four cases (sensitivity: 80%) and positive cytology in two cases. This preliminary pilot study shows FISH can be a useful tool for the detection of recurrence during a follow up of bladder cancer.