Abstract: Objective： To analyze the clinical pathologic characteristics of cases with fluorescence in situ hybridization (FISH) positive of exfoliated urothelial cells, so as to evaluate the clinical utility of FISH in the diagnosis of urothelial carcinoma (UC). Methods: A total of 271 cases of FISH positive in Department of Urology of Peking University First Hospital from Apr. 2012 to Sep. 2015 were recruited in this study. Retrospective analysis was made on their clinical data. For FISH analysis, labeled probes specific for chromosomes 3, 7, 17, and the p16 (9p21) gene were used to assess chromosomal abnormalities indicative of malignancy. The positive predict values (PPV) of all the techniques were analyzed. Results: Of the 271 patients, 207 cases were UC, 7 cases were non-UC, and 57 cases were benign diseases. The PPV of FISH in detecting UC was 76.4%, while the 95% confidence interval (CI) 71.3% to 81.5%. In the cohort of FISH positive, this value was similar to that of urinary cytology (PPV 86.8%, 95% CI: 78.5%-95.0%). The PPV of FISH was lower than that of cystoscopy and ureteroscopy (PPV 96.1%, 95% CI: 91.7%-100.0%). There were significant differences between this study and the PPV of FISH reported abroad (PPV 53.9%, χ2=33.048, P<0.001). Of all the UC with FISH positive, bladder cancer showed an earlier pathological stage versus renal pelvic carcinoma and ureteral carcinoma, with significance (χ2=5.894, P=0.015, and χ2=13.601, P<0.001, respectively). However, no difference was found in the size, pathological stage and pathological grade of tumors between the urinary cytology positive group and the urinary cytology negative group. The rate of high-grade UC in ureteral carcinoma of FISH positive was 92.3%, much higher than that of ureteral carcinoma reported domestically. Conclusion: The PPV of FISH in detecting UC is higher relatively, with a better clinic value for Chinese patients. The ureteral carcinoma with FISH positive obtains a higher pathological grade, which is of great guiding significance for UC.

Key words: In situ hybridization, fluorescence, Urothelial carcinoma, Molecular probes, Diagnosis