Comparison of fluorescence in situ hybridization -FISH- and conventional cytology for early detection of urothelial carcinoma

Nadina Erill 1, Anna Colomer 1, Míriam Gorriz 1,2, Naim Hannaoui 3, Ruth Román 1, Maria Conangla 2, Josep M Banús 3, Carlos Cordon-Cardo 4, Xavier Puig 1,2.

1BIOPAT, Grup Assistència, Barcelona, Spain; 2HISTOPAT Laboratoris, Barcelona, Spain; 3Institut Català d’Urologia i Nefrologia, ICUN; Barcelona, Spain; and 4Division of Molecular Pathology, Memorial Sloan-Kettering Cancer Center, New York, USA.

Bladder tumors have a high recurrence rate, so treated patients are followed for detection of potential new lesions. Cystoscopy and cytology have been the standard methods for diagnostic and clinical follow-up. However, the sensitivity of cytology in urine specimens is limited, most low-grade tumors not being identified. The aim of our study was to evaluate the utility of the UroVysion multi-color FISH (Vysis) assay in urine specimens for the early detection of bladder cancer and recurrent lesions, comparing the results with those obtained by conventional urine cytology. A total of 115 urine specimens from 80 patients were analyzed both by cytology and FISH. Fluorescent labeled probes directed to the centromeres of chromosomes 3, 7, 17, and to 9p21 band (P16 locus) were used to evaluate chromosomal abnormalities associated with uroepithelial tumors. A positive diagnosis was confirmed either clinically, by cytology and biopsy, or by imaging in 29 samples. The frequency of FISH positive results in these samples was 83%, compared with 58% of the cytology. FISH was positive in 2 patients with negative follow-up cystoscopy results. No positive FISH results were obtained among the 86 samples on which bladder tumor was not diagnosed. The superiority of multi-probe FISH in terms of sensitivity (83% compared to 59% for cytology), together with its high specificity and positive predictive value (both 100%), makes this test very useful for the early detection of uroepithelial tumors in urine specimens.

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Abstract in J Mol Diagn 2004; 6: 430 (ST20).