Molecular genetic methods in the diagnosis of invasive bladder cancer

Development and progression of tumours is generally driven by an accumulation of genetic alterations. In this study we correlated chromosome 17 aneuploidy to invasiveness of bladder cancer by the method of fluorescence in situ hybridisation (FISH) in urinary cytospins. We investigated the value of FISH compared to DNA cytophotometry in the diagnosis of bladder cancer. 39 patients with or suspicious for bladder tumour were analyzed. 19 patients had a bladder tumor at the time of diagnosis, 14 superficial (Ta-T1) and 5 invasive (T2-3). The remaining 20 patients had no tumour at the time of diagnosis, however 9 of them had one in prehistory (Ta-T2). For FISH we used the DNA probe of HER-2/neu located on chromosome 17. DNA image cytometry was performed according to single cell interpretation of Böcking. Our results showed a correlation between HER-2/neu CEP 17 alterations and invasive bladder cancer to the extent of 10-70% aberrant cells for patients with current invasive bladder tumour as well as for patients who had been cured but with as invasive bladder cancer in prehistory. On the other hand, the percentage of aneuploid cells for negative biopsy and superficial tumour was 0-2%. The DNA cytophotometry brought an uniform aneuploidy only for present invasive tumours: negative biopsies, superficial cancer and invasive tumour just in prehistory, showed mixed diploid-aneuploid DNA patterns. Our results showed that for the detection of aberrant tumour cells the method of FISH is more sensitive than DNA cytometry. FISH could provide important information in the prognosis of bladder cancer.