Molecular genetic methods in the diagnosis of invasive bladder cancer

Development and progression of tumours is generally driven by an accumulati on of genetic alterations. In this study we correlated chromosome 17 aneupl oidy to invasiveness of bladder cancer by the method of fluorescence in sit u hybridisation (FISH) in urinary cytospins. We investigated the value of F ISH compared to DNA cytophotometry in the diagnosis of bladder cancer. 39 p atients with or suspicious for bladder tumor were analyzed. 19 patients had a bladder tumor at the time of diagnosis, 14 superficial (Ta-Tl) and 5 inv asive (T2-3). The remaining 20 patients had no tumour at the time of diagno sis, however 9 of them had one in prehistory (Ta-T2). For FISH we used the DNA probe of HER-2/neu located on chromatosome 17. DNA image cytometry was performed according to single cell interpretation of Bocking. Our results s howed a correlation between HER-2/neu CEP 17 alterations and invasive bladd er 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 wit h as invasive bladder cancer in prehistory. On the other hand the percentag e of aneuploid cells for negative biopsy and superficial tumour was 0-2%. T he DNA cytophotometry brought an uniform aneuploidy only for present invasi ve tumours; negative biopsies, superficial cancer and invasive tumour just in prehistory, showed mixed diploid-aneuploid DNA patterns. Our results sho wed that for the detection of aberrant tumour cells the method of FISH is m ore sensitive than DNA cytometry. FISH could provide important information in the prognosis of bladder cancer.