The expression of thymidine phosphorylase is a prognostic predictor for the intravesical recurrence of superficial bladder cancer.

BACKGROUND: Thymidine phosphorylase (TP), also known as platelet-derived endothelial cell growth factor, has been implicated in the angiogenesis of bladder cancer. The aim of this study is to investigate the association between TP expression and the clinicopathologic findings, and the prognostic value.
METHODS: TP immunohistochemical staining was performed in specimens from 71 patients (50 men and 21 women) with superficial bladder cancer (pTa or pT1). Thirty-nine patients had received intravesical instillation of tetrahydropyranyladriamycin (THP) after transurethral resection (TUR) and the other 32 had not. For immunohistochemistry, paraffin-embedded specimens were stained with mouse monoclonal antibody against TP. When more than 10% of tumor cells were positively stained, staining was defined as positive. The correlations between TP immunostaining and clinicopathological features were analyzed. Multivariate analysis, using the Cox proportional hazard model, was performed to determine the risk factors for intravesical recurrence.
RESULTS: Specimens from 29 of the 71 patients (19 men and 10 women) were positive for TP. The expression of TP was not correlated with age, sex, histological grade, multiplicity, or morphology. Also, TP expression was not associated with whether the cases were primary or recurrent. Multivariate analysis demonstrated that the decreased expression of TP and the use of THP instillation could be independent predictors of a higher rate of intravesical recurrence-free bladder cancer.
CONCLUSION: The present study suggests that immunohistochemical TP staining is useful for predicting the intravesical recurrence of superficial bladder cancer after Transurethral resection of bladder tumor (TUR-Bt).