NMP22 in transitional cell carcinoma of the urinary bladder

Urinary bladder transitional cell carcinoma (TCC) is a common cancer encountered in the human urinary system. The detection of new and recurrent TCC of the urinary bladder was performed using nuclear matrix (NMP22) kit and compare to the urine cytology.

Ninety-two patients were included and divided to 3 groups. The first group was composed of patients for detection of recurrence of TCC of the urinary bladder in follow-up check. The second group consisted of patients who had microscopic or gross hematuria. The third group was volunteers. A urine sample was obtained from every enrolled patient. Followed by cystourethroscopy, the urine cytoloy, urine analysis and NMP 22 were performed respectively. A receiver operating characteristics (ROC) curve was constructed to determine NMP22 cutoff value for optimal sensitivity and specificity to detect bladder tumor. The data was then analyzed with Student-t test.

ROC curve showed an optimal value of greater than 10 units per mL in differentiating positive from negative results. The sensitivity of NMP22 was 91.7% (22/24) and the specificity was 72.1% (49/68) in detection of TCC. The sensitivity and specificity of cytology were 37.5% (9/24) and 97.1% (66/68), respectively. The positive predictive values of NMP22 and cytology were 53.7% and 81.8%, individually. The false-positive rate of NMP22 was 27.9%. More sensitivity was observed in the NMP22 test with regards to high-grade and advanced-stage tumors.

NMP22 is a highly sensitive tumor marker. However, high false positive rate and unsatisfactory positive predictive value are the drawbacks of this new tumor marker assay. There is inadequate evidence to consider total replacement of cytology with NMP22. But combination of NMP22 and cytology could be the most complete way to avoid unnecessary cystoscopic surveillance.