Abstract: Objective To investigate the expression of cancerous inhibitor of protein phosphatase 2A (CIP2A) in bladder urothelial carcinoma tissues and its relationship with clinical pathologic characteristics，and to discuss the feasibility of CIP2A as prognostic markers. Methods RT-PCR and Western blot were used to evaluate the mRNA and protein expression of CIP2A in cancer tissues and corresponding paracancerous tissues from 25 bladder urothelial carcinoma patients.A tissue microarray (TMA) containing specimens from 117 bladder urothelial cell carcinoma tissues and 30 paracancerous tissues was constructed and then immunohistochemistry was used to examine the protein expression of CIP2A.The correlations between CIP2A and clinicopathological characteristics and prognosis were also analyzed. Results CIP2A mRNA and protein were undetectable or very low in paracancerous tissues,but were dramatically elevated in cancer samples in 25 patients.The positive expression rate of CIP2A protein in bladder urothelial cell carcinoma tissues 76.9% (90/117) was significantly higher than that in paracancerous tissues 6.7% (2/30).Such difference had statistic significance(P＜0.001).CIP2A expression correlated with histological grade (P＜0.001),tumor stage (P＜0.001),tumor diameter (P=0.002) and lymph nodes metastasis (P=0.046)；while it was not related with age,gender,tumor number and tumor recurrence (P＞0.05).Kaplan-Meier univariate analysis showed that the overall and recurrence-free survival rates were significantly higher in the group with low expression of CIP2A than in the group with high expression of CIP2A (P＜0.001).Cox proportional hazards model revealed that tumor stage，histological grade,and CIP2A expression were independent predictors of an unfavorable prognosis for overall survival rate (P＜0.001,P=0.001 and P=0.035,respectively ) and recurrence-free survival rates (P＜0.001,P＜0.001 and P=0.003,respectively ). Conclusion The expression of CIP2A protein is significantly increased in bladder urothelial cell carcinoma tissues,which may be involved in the progress of bladder urothelial cell carcinoma.CIP2A may be a valuable biomarker for assessing the prognosis of bladder urothelial cell carcinoma.