Numerical aberrations of chromosome 8 and allelic loss at 8p in non-muscle-invasive urothelial carcinomas of the urinary bladder

Objectives: Cytogenetic and molecular studies indicate that the development and progression of bladder cancer involves multiple and complex genetic ev ents. We screened 39 primary T-a and T-1 transitional cell carcinomas of th e urinary bladder for numerical changes of chromosome 8 and for the presenc e of relative allelic loss at 8p. The results were compared with the histop athologic stage and grade and with tumour recurrence. Methods: Thirty-nine paraffin-embedded transurethral resection specimens co ntaining bladder cancer were examined by interphase cytogenetics with a pro be specific for chromosome 8. DNA from tumour cells and normal tissue was p repared after microdissection. Allelic loss was assessed by PCR-based micro satellite analysis. Results: Numerical aberrations of chromosome 8 were present in 20 of the 39 cases (51.3%) and were significantly associated with a higher tumour grade and stage. Ten cases (25.6%) displayed allelic losses at 8p. Sixteen patie nts (41%) suffered from tumour recurrence, but Kaplan-Meier analysis and th e log-rank test did not show any statistically significant correlation betw een tumour grade, stage, numerical aberrations of chromosome 8, allelic los ses of 8p and freedom from disease recurrence. Conclusions: In this group of patients with non-muscle-invasive bladder can cers, numerical and structural aberrations at chromosome 8 are associated w ith a higher tumour grade and stage, but not with tumour recurrence. Copyri ght (C) 2000 S. Karger AG, Basel.