Utility of fluorescence in situ hybridization in the diagnosis of upper urinary tract urothelial carcinoma

The purpose of this study was to evaluate the clinical utility of fluorescence in situ hybridization (FISH) assay as a non-invasive method for diagnosing and monitoring urothelial carcinoma (UC) in the upper urinary tract (UUT). Urine specimens from 21 consecutive patients with UUT-UC and 10 healthy controls were analyzed by means of cytology and FISH. For FISH analysis, labeled probes specific for chromosomes 3, 7, and 17 and for the p16 (9p21) gene were used to assess chromosomal abnormalities indicative of malignancy. Sensitivity and specificity of both techniques were determined and compared. The frequency of chromosomal aberrations of malignant cells from UUT was also determined. Overall sensitivity of FISH was significantly higher than that of urine cytology (85.7% vs. 23.8%, p = 0.0009). Specificities for both FISH and cytology were 100% (p = ns). Of 21 patients with UUT-UC, polysomies of chromosome 3, 7 and 17 were observed in 57.1%, 52.4% and 28.6%, respectively, and loss of the p16 gene in 47.6%. FISH has a higher sensitivity than cytology and a similar specificity in dectecting UUT-UC. It may be a promising non-invasive tool for the diagnosis and surveillance of UUT-UC.