Downregulation of pigment epithelium-derived factor is associated with increased epithelial-mesenchymal transition in bladder cancer

BACKGROUND: Pigment epithelium-derived factor (PEDF) has been reported to inhibit angiogenesis in bladder cancer, but whether it modulates epithelial-mesenchymal transition (EMT) remains unknown. METHODS: We have included 68 samples of non-muscle invasive bladder cancer in this study. Immunohistochemistry was performed in all sample sections for expressions of PEDF, SNAI2, Vimentin and E-cadherin, which were quantified and The EMT Index (EMTi) was calculated by Vimentin/E-cadherin. Levels of expression were studied for correlations with clinicopathological parameters. RESULTS: Patients were grouped with high (EMTi <= 1) and low (EMTi > 1) EMT level for comparisons of clinicopathological parameters. In the univariate analysis, EMT level was shown to be significantly associated with tumor onset and PEDF level, but not with gender, occurrence, stage, grade, or SNAI2 level. Further multivariate analysis revealed that PEDF level was significantly negatively correlated with EMTi independent of other clinicopathological parameters. CONCLUSIONS: Our results indicate that PEDF may serve as a promising novel modality for the treatment of bladder cancer, as it can inhibit not only angiogenesis but also EMT process of bladder cancer.