Fluorescence in situ Hybridization in the Diagnosis of Transitional Cell Carcinoma

Abstract

Background: Cystoscopy is still considered to be the ‘Gold Standard’ in the diagnosis or urinary bladder cancer. However, this invasive technique is not free from subjective influences, especially in cases of superficial tumors of low malignancy. As is the case with cytological detection methods, cystoscopy suffers from a diagnostic gap in the early detection of urothelial carcinomas. Molecular genetic methods, on the other hand, are objective with regard to evaluation of early changes before any macroscopic tumor detection. Cytogenetic analyses of transitional cell carcinomas show structural changes of chromosomes 1, 3, 5, and 8 along with numerical aberrations of chromosomes 7, 8, 9, 10, and the Y chromosome. The detection of these changes in in vitro studies proved to be difficult for the need to establish tumor cell lines. Consequentially, fluorescence in situ hybridization (FISH) could be used as an alternative method to detect cytogenetic changes. Patients and Methods: Since 1995 we investigated 95 patients suffering from urinary bladder carcinoma in a prospective study. FISH was carried out on cells from spontaneous urine samples and bladder washes in parallel with conventional cytology. For chromosomes 7, 8, 9, and 12 centromere probes were used. Results: Comparing results on spontaneous urine samples and on bladder washes, the sensitivity of detecting tumor cells obtained by FISH was 27/32% (pTa), 72.6/92.8% (T1G1–2), and 73.3/86.6% (≤ pT1G3 and > pT1), respectively. In cases with papillomas and cystitis as well as in a control group, FISH yielded no false-positive results. Conclusion: Our data show that FISH is an objective, appropriate technique for diagnosis and follow-up of transitional cell carcinoma and represents a valuable complementation to the conventional cytological investigations.