Alpha-catenin expression has prognostic value in local and locally advanced prostate cancer

Normally functioning cell-cell adhesion plays an important role in the maintenance of tissue architecture and cell cohesion. E-cadherin is an important adhesion molecule of epithelial cells. In many types of cancer the expression of E-cadherin is reduced leading to increased risk of disease progression. alpha-Catenin is one of the intracellular elements of the E-cadherin-catenin complex. The abnormalities in the expression of alpha-catenin seem to associate with malignant cellular features and disease progression in prostate cancer. To further analyse the significance of alpha-catenin expression, we studied 215 cases of prostate cancer by immunohistochemistry and the results were related to other known prognostic factors and patient survival during a mean follow-up period of 13 years. alpha-Catenin expression was down-regulated in 19% of the cases and 3% of the tumours were totally alpha-catenin-negative. The abnormal alpha-catenin expression and cytoplasmic signal were significantly linked with high T-category, metastatic disease, high Gleason score, perineural growth, high mitotic rate, high S phase fraction and DNA aneuploidy (P < 0.05 for all). In the survival analysis, reduced alpha-catenin expression (P = 0.06) and cytoplasmic signal (P = 0.04) were related to unfavourable patient outcome. In the multivariate analysis, including TM-classification and Gleason score, alpha-catenin expression had independent prognostic value in T1-2 M0 tumors. In the M0 tumours, abnormal alpha-catenin signal was independently associated with recurrence-free survival as well. The results indicate that down-regulation of alpha-catenin is related to several malignant cellular features, and it seems to have prognostic significance in the early phases of cancer progression. We suggest that alpha-catenin expression can provide prognostic information in early prostate cancer.