Usefulness of urinary nuclear matrix protein 22 (NMP22) as a marker for transtional cell carcinoma of the bladder

Objectives: The purpose of this study was to evaluate an immunoassay for urinary nuclear matrix protein, NMP22, as a novel marker for urothelial cancer. Patients and Methods: NMP22 values were determined for 71 patients and 21 healthy volunteers. Each subject provided a single (3 voids) urine sample for analysis at the time of entry into the study. Each sample was assayed for levels of NMP22. Results: When the cut-off value was set at 10 U/ml, the positive rare for urinary NMP22 in bladder cancer was 37.8% (17 out of 45), whereas that in post-treatment cases and benign diseases was 30.8% (8 out of 26) compared to 14.3% (3 out of 21) for healthy volunteers. This cut-off value provided a sensitivity of 37.8% and a specificity of 80.9%. In the bladder cancer group, NMP22 levels were related to tumor size, shape, grade and stage. Conclusions: Despite the many reports that suggest NMP22 as a promising urinary marker for monitoring transitional cell carcinoma, this study does not support its usefulness as a substitute tool for urinary cytology in the control of bladder tumors.