Objective: To analyze chromosomal abnormalities in macroscopically normal urothelium in patients with bladder pT1 and pT2a urothelial carcinoma and correlate the changes with histologic features.
Study design: Cytologic touch preparations of the tumors and of the adjacent and distant urothelium were obtained from 8 bladders with urothelial carcinoma. Fluorescence in situ hybridization (FISH) was used to detect abnormalities of chromosomes 3, 7, 9 and 17 and of the 9p21 locus.
Results: The macroscopically normal urothelium adjacent to and distantfrom neoplastic foci was either normal looking microscopically or showed histologic changes ranging from hyperplasia to dysplasia and carcinoma in situ. FISH analysis detected chromosome gains and 9p21 deletion similar to those present in the urothelial carcinoma even though the percentage of altered nuclei was lower, especially in hyperplasia. The microscopically normal urothelium showed minor abnormalities in terms of gain for all the chromosomes investigated.
Conclusion: Even though urothelium looks normal from the macroscopic point of view, it frequently harbors histologic changes and chromosomal abnormalities. These findings are of clinical significance since they might represent genetic alterations involved in recurrence and/or progression of urothelial carcinoma.