Epithelial-Mesenchymal Transition Markers β-catenin, Snail, and E-Cadherin do not Predict Disease Free Survival in Prostate Adenocarcinoma: a Prospective Study

Current methods for diagnosis and staging of prostate adenocarcinoma are not sensitive enough to distinguish between patients with indolent disease and those that should receive radical treatment. Epithelial-mesenchymal transition (EMT) is a well-characterized process involved in tumor invasion and metastasis. The aim of this study is to analyze the expression of β-catenin, Snail, and E-cadherin in prostate cancer patients with prospective evaluation of their value in predicting disease-free survival (DFS). One-hundred-and-three consecutive prostate carcinoma patients who underwent radical prostatectomy and 35 patients with benign prostate hyperplasia (BPH) were enrolled. Age, initial PSA level, tumor size and clinical stage were documented for adenocarcinoma patients and they were enrolled in active surveillance with serum PSA levels. Recurrence was defined as PSA level of ≥ 0.2 ng/ml on at least 2 occasions over a 2-month period. Immunohistochemical staining intensity was scored as negative, weakly positive, moderately positive, and strongly positive. For Snail and β-catenin immunoreaction, the tumors were considered nuclear positive when more than 5 % of the nuclei of tumor cells were positively stained. Patients with prostate cancer had weaker β-catenin (p < 0.0001), Snail (p = 0.006), and E-cadherin (p = 0.02) staining when compared to BPH patients and the frequency of nuclear positivity for β-catenin and Snail were higher in adenocarcinoma group (p < 0.0001). Increased expression and nuclear positivity of β-catenin were associated with advanced stage (p = 0.012 and p = 0.003) and higher tumor volume (p = 0.013 and p = 0.002). Additionally, patients with increased Snail expression had higher Gleason scores and tumor volume at presentation (p = 0.008 and p = 0.004). However, there were no significant DFS differences in adenocarcinoma patients who did and did not have β-catenin, Snail, and E-cadherin expression as assessed with log-rank test. Expressions of β-catenin, Snail, and E-cadherin were significantly lower in prostate cancer patients compared to BPH patients and both β-catenin and Snail had nuclear staining pattern in patients with adenocarcinoma. However, none of these markers predicted DFS in 36-month follow up of our cohort.