Objective To determine the relationship between expression of topoisomerase Ⅱ α and clinicopathological factors,overall survival in colorectal caner.Methods Expression of topoisomerase Ⅱ α was measured using EnVision immunohistochemistry in 490 colorectal cancer patients.The relationship between topoisomerase Ⅱ α expression and various clinicopathological parameters was analyzed.Kaplan-Meier analyses and multivariate analyses were used to evaluate the significance of topoisomerase Ⅱ α expression in prognosis prediction.Results Overexpression of topoisomerase Ⅱ α was found to be related with lower T stage ( P =0.042 ),lower N stage ( P =0.038 ),and possibly with lower recurrence rate ( P =0.053 ).Kaplan- Meier analyses showed that overexpression of topoisomerase Ⅱ α was related with prolonged overall survival (P =0.022 ) and prolonged disease-free survival ( P =0.036).Multivariate analyses showed that elevated serum CEA ( P ＜ 0.001 ),elevated serum CA199 ( P =0.002 ),poor differentiation ( P =0.001 ),advanced Dukes stage ( P ＜ 0.001 ) and lower expression of topoisomerase Ⅱ α( P =0.017 ) were independent predictive factors for poor prognosis.Conclusions Expression of topoisomerase Ⅱ α is a favorable predictive factor for colorectal cancer,and would be useful in prognosis prediction and treatment selection for early colorectal cancer and malignant colorectal polyps,especially when it is used in combinations with serum CEA,CA199 and differentiation.