Abstract: BACKGROUND ＆ AIM: To evaluate the value and potential clinical implications of microsatellite instability(MSI) in diagnosis of bladder cancer recurrence. MATERIAL AND METHODS: The analysis by PCR for detecting MSI was done in 20 cases of nomal samples and 60 cases of urine samples from 42 patients with bladder carcinoma in postoperative follow-up. The analytic parameters included hematuresis ,tumor size, number of tumor, tumor grade and 5 microsatellite bio-markers. RESULTS: There were 17 cases of MSI＋ in 20 recurrent cases, of which 15 cases got hematuresis samples. The sensitivity, specificity and positive predictive value was 85.00％, 82.50％ and 83.33％, respectively, with the analysis by the results of MSI in diagnosis of bladder cancer recurrence. No correlation was found between MSI and tumor grading. CONCLUSION: The results indicate that MSI is a good bio-marker in diagnosis of bladder cancer recurrence for patients with bladder carcinoma in postoperative follow-up, especially for which with hematuresis.

Key words: bladder neoplasm, hematuresis, recurrence, microsatellite instability