Comparative study of ProEx C immunocytochemistry and UroVysion fluorescent in-situ hybridization assays on urine cytology specimens

Detection of urothelial carcinoma (UC) by urine cytology can be challenging. Recently, ProEx C has been studied as a marker to improve detection of UC. ProEx C is an assay targeting expression of topoisomerase IIa and minichromosome maintenance protein-2 and is currently utilized to assist in diagnoses of the gynecological specimens. In this study, we compared the utility of ProEx C and UroVysion in urine specimens. Twenty-seven urine specimens with UroVysion assay analysis and surgical biopsy follow-up were selected. The smears were stained with ProEx C. ProEx C and UroVysion assay results were separated into two categories based on surgical biopsy follow-up (benign or neoplastic). Surgical biopsy diagnoses were used as the gold standard for comparative evaluation of the two assays. The surgical follow-up was 9 benign, 2 low grade, and 16 high grade UCs. The sensitivity was 88.9% for ProEx C and 55.6% for UroVysion, while the specificity was 77.8% for ProEx C and 44.4% for UroVysion. Positive predictive value was 88.9% for ProEx C and 66.7% for UroVysion. Negative predictive value was 77.8% and 33.3% for ProEx C and UroVysion, respectively. Using the two-tailed paired t-test, P value of 0.033 was obtained when ProEx C stain was compared with the UroVysion assay. ProEx C immunocytochemistry has a more favorable performance than fluorescent in-situ hybridization with a significant difference between the two assays using paired two-tail t-test (P = 0.0033).