Microsatellite Instability Profiling in Egyptian Bladder Cancer Patients: A Pilot Study

Microsatellite alterations have been implicated in the pathogenesis of many cancers; however, they are still not well addressed in the bladder cancer (BC) of Egyptian population. We assessed microsatellite instability (MSI) profile and loss of heterozygosity (LOH) using 13 microsatellite markers in tumor tissue samples and urine sediments obtained from 30 Egyptian patients with BC. The concordance between MSI in tumor tissue and urine samples was determined, and correlated to relevant clinicopathologic features. We found that MSI was more frequent than LOH (100% and 46.7%, respectively). D16S310, MBP, and IFN-α showed the highest MSI frequency in urine samples (70%, 70%, and 66.67%, respectively), while MBP, ACTBP2, and D9S171 (66.67%, 63.33%, and 60%, respectively) were the most frequently detected in tumor tissues. All assessed MSI markers correlated significantly with pathologic subtype (being more frequent in TCC) and with hematuria. The concordance between tissue and urine samples was statistically significant for D16S476, D9S171, FGA, and ACTBP2 (P = 0.04, 0.015, 0.02, and 0.007, respectively). When we combined D16S476 and D9S171, the sensitivity, specificity, positive predictive value, and negative predictive value for the diagnosis of BC were 80.0%, 75.0%, 82.8%, and 71.4%, respectively. Accordingly, we concluded that MSI in urine sediments could be a potential tool for the diagnosis of BC.