DOI:10.1111/j.1365-2303.2008.00586.x Could nuclear matrix protein 22 (NMP22) play a role with urine cytology in screening for bladder cancer? – experience at Kuwait University K. Kapila*   , E. O. Kehinde à , J. T. Anim*, O. A. Mojiminiyi § , A. Vinsu à , S. S. George – , M. Al-Maghrebi** and F. Al-Mulla* *Department of Pathology, Faculty of Medicine, Kuwait University, Safat,   Cytology Laboratory, Mubarak Al-Kabeer Hospital, Kuwait, Safat, à Department of Surgery, Faculty of Medicine, Kuwait University, Safat, § Clinical Chemistry Unit, Department of Pathology, Faculty of Medicine, Kuwait University, Safat, – Cytology Laboratory, Department of Pathology, Faculty of Medicine, Kuwait University, Safat and **Department of Biochemistry, Faculty of Medicine, Kuwait University, Safat, Kuwait Accepted for publication 3 April 2008 K. Kapila, E. O. Kehinde, J. T. Anim, O. A. Mojiminiyi, A. Vinsu, S. S. George, M. Al-Maghrebi and F. Al-Mulla Could nuclear matrix protein 22 (NMP22) play a role with urine cytology in screening for bladder cancer? – experience at Kuwait University Objectives: This prospective study was undertaken to evaluate nuclear matrix protein (NMP22) compared to urine cytology in the detection of bladder cancer and also to determine whether indexing suspicious cytology to NMP22 could enhance the clinical utility of cytology. Methods: Cytological findings of voided urine collected prior to a cystoscopic biopsy were correlated with urine NMP22 assay in 46 patients attending the urology clinic in Mubarak Al-Kabeer Hospital. The patients were clinically categorized into newly diagnosed cases of transitional cell carcinoma (TCC), recurrent TCC, TCC in remission and controls. Results: Using histological diagnosis as the gold standard the sensitivity and specificity of NMP22 were 78% and 43% respectively and of cases with malignant urine cytology were 30% and 87% respectively. If suspicious and malignant cytology were combined as positive results the sensitivity increased significantly to 87% while the specificity decreased but not significantly to 74%. Suspicious or malignant cytology enhanced by positive NMP22 gave a sensitivity of 70% and specificity of 87% neither of which was significantly different from cytology alone. There were three false positive cases on cytology and 13 false positive cases on NMP22 assay. There were three false negative cytology and five false negative NMP22 cases but only one was false negative for both, resulting in a high sensitivity (96%) but low specificity (30%) if either positive NMP22 or malignant or suspicious cytology was taken as a positive result. Conclusion: Combining NMP22 with malignant or suspicious cytological result improved sensitivity for the detection of bladder cancer but with a major decrease in specificity, suggesting a potential role in screening rather than diagnosis. Keywords: bladder cancer, urine cytology, NMP22, suspicious cytology, sensitivity, specificity Introduction Bladder cancer is one of the most common genitouri- nary malignancies and 60% of patients with newly diagnosed transitional cell carcinoma (TCC) will recur within 5 years of initial diagnosis and treatment. 1 Standard surveillance techniques for disease Correspondence: K. Kapila, MD, FAMS, FIAC, FRCPath., Professor & Head Cytology Unit, Department of Pathology, Faculty of Medicine, Kuwait University, P.O. Box 24923, Safat 13110, Kuwait. Tel.: +965 531 9476; Fax: +965 533 8905; E-mail: kkapila@yahoo.com Cytopathology 2008, 19, 369–374 ª 2008 The Authors Journal compilation ª 2008 Blackwell Publishing Ltd 369