USP28 is a potential prognostic marker for bladder cancer

This study was conducted to analyze the expression of the ubiquitin-specific protease Usp28 and assess its clinical significance in human bladder cancer. mRNA and protein expression levels of Usp28 were determined by real-time polymerase chain reaction (PCR) and Western blot in 24 paired bladder cancers and the adjacent non-cancerous tissues. In addition, the expression of Usp28 protein in 186 bladder cancers was also determined by immunohistochemistry. The relationship between expression of Usp28 and clinico-pathologic features and prognosis was finally evaluated. Usp28 was expressed at a higher level in bladder cancers compared to adjacent non-cancerous tissues at both the mRNA and protein levels in 24 paired samples (all P < 0.01). In immunohistochemical examination, 78 (41.9 %) of 186 cases displayed low Usp28 expression in cancerous tissues, whereas 108 (58.1 %) cases displayed high Usp28 expression. In the universal analysis, Usp28 correlated strongly with histopathological grade, clinical stage, tumor number and recurrence rate (P = 0.0001, 0.0001, 0.0001 and 0.0051, respectively), but did not correlate with gender or age (P = 0.5588 and 0.6574). After multiple analysis of the above factors and consideration of confounding factors, tumor number, histological grade, clinical stage, and recurrence were related to Usp28 expression (P = 0.001, 0.001, 0.001 and 0.001, respectively). Finally, Usp28 expression was indentified as a independent predictors of survival (P = 0.001). Usp28 protein expression is potentially valuable in prognostic evaluation of bladder cancer.