p53 and vimentin double immunostaining to differentiate between high-grade urothelial carcinoma cells and benign atypical cells

Introduction: Urine cytology is an indispensable test for detecting high-grade urothelial carcinoma (HGUC); however, the distinction between HGUC cells and morphologically similar benign atypical cells poses clinical challenges. In this study, we performed double immunostaining for p53 and vimentin to establish a diagnostic method to accurately distinguish HGUC cells from benign atypical cells. Methods: This study included 41 cases of HGUC, 11 of urolithiasis, and 22 of glomerular disease diagnosed histopathologically or clinically. After preparing urine cytology specimens from voided urine samples, p53 immunostaining was performed, and the p53 positive intensity and p53 positivity rate were calculated. Subsequently, vimentin immunostaining was performed on the same specimens to calculate the rate of vimentin positivity. Results: The HGUC cell group had a mean p53 positive intensity of 2.40, a mean p53 positivity rate of 73.2%, and a mean vimentin positivity rate of 5.1%. In contrast, the mean p53 positive intensity, p53 positivity rate, and vimentin-positivity rate was 1.63, 36.7%, and 66.2%, respectively, in the benign atypical cell group. There were significant differences between the two groups for each parameter. Moreover, two multiple logistic regression models combining the results of these three parameters exhibited higher sensitivity and specificity than solely assessing the p53 positive intensity, positivity rate, and vimentin positivity rate. Conclusion: Since double immunostaining with p53 and vimentin distinguishes HGUC cells from benign atypical cells, it could be used to improve the diagnostic accuracy of urine cytology.