EVALUATION OF NMP22 IN THE DETECTION OF TRANSITIONAL-CELL CARCINOMA OF THE BLADDER

Purpose: Urinary nuclear matrix protein (NMP22) was evaluated for dete ction of new and recurrent bladder tumors in patients with a history o f transitional cell carcinoma. Our objective was to determine sensitiv ity and specificity of this marker for tumors of various stages and gr ades, as well as its use as an adjunct to or substitute for urinary cy tology. Materials and Methods: A total of 231 patients with a history of transitional cell carcinoma provided 288 voided urine samples befor e cystoscopic examination at 1 of 3 institutions (53 patients were ree valuated at least once). Urine samples were assayed for NMP22 using th e NMP22 Test Kit.dagger Select patients underwent biopsy with appropri ate additional therapy. Voided urinary cytology was obtained in 200 ca ses. End points for determination of the absence and presence of tumor were negative cystoscopy and positive biopsy, respectively. A receive r operating characteristics curve was constructed to determine the opt imal NMP22 threshold for detection of transitional cell carcinoma. For positive biopsies NMP22 values were also correlated with tumor stage and grade. Comparison to cytology was limited to patients with complet e data. Results: There were 208 negative cystoscopies (158 with cytolo gy) and 66 positive cystoscopies with biopsy (42 with cytology). Of th e cases 14 were eliminated from statistical analysis due to incomplete data. Receiver operating characteristics curve interpretation determi ned that 6.4 units per mi. was an optimal reference value for detectio n of transitional cell carcinoma in this patient group. Sensitivity an d specificity for all pathological groupings was 68 and 80%, respectiv ely. When compared to cytology the sensitivities of NMP22 and cytology were 67 versus 31 or 40% (depending on the definition of positive cyt ology). Conclusions: NMP22 values represented significant improvement over urinary cytology for detection of transitional cell carcinoma. Th e sensitivity of NMP22 for detection of transitional cell carcinoma in bladder cancer patients was as much as twice that of cytology when a reference value of 6.4 units per mi. was used. NMP22 analysis was less costly than cytology and operator independent. While NMP22 has previo usly been shown to be a strong predictor of recurrence after tumor res ection, it is an effective and sensitive screening test for detecting tumors in patients with transitional cell carcinoma.