Background: Optimal treatment for prostate cancer remains a challenge worldwide. Recently, T cellimmunoglobulin mucin-3 (TIM-3) has been implicated in tumor biology but its contribution prostate cancerremains unclear. The aim of this study was to investigate the role of TIM-3 as a prognostic marker in patientswith prostate cancer. Methods: TIM-3 protein expression was determined by immunohistochemistry andWestern blotting in 137 prostate cancer tumor samples and paired adjacent benign tissue. We also performedcell proliferation assays using 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl- 2H tetrazolium bromide (MTT) andcell invasion assays. The effects of small interfering RNA (siRNA)-mediated knockdown of TIM-3 (TIM-3siRNA) in two human prostate cancer cell lines were also evaluated. Results: TIM-3 expression was higher inprostate cancer tissue than in the adjacent benign tissue (P<0.001). High TIM-3 expression was an independentpredictor of both recurrence-free survival and progression-free survival. TIM-3 protein was expressed in bothprostate cancer cell lines and knockdown suppressed their proliferation and invasion capacity. Conclusions:TIM-3 expression is associated with a poor prognosis in prostate cancer. Taken together, our resutlts indicatethat TIM-3 is a potential prognostic marker in prostate cancer.
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