OBJECTIVETo investigate the expressions of E-cadherin (E-cd) and alpha-catenin (alpha-cat) proteins in benign and malignant prostate tumors, and determine whether they could be used as molecular markers for the prognosis of prostate cancer (PCa).

METHODSWe detected the expressions of E-cd and alpha-cat in the prostatic tissues from 45 cases of PCa and 10 cases of benign prostatic hyperplasia (BPH) by immunohistochemical Elivision staining, and analyzed the relationships of E-cd and alpha-cat expressions with the PCa stage, PCa grade, preoperative PSA, results of endocrine therapy and prognosis.

RESULTSThe E-cd protein was abnormally expressed in 86.7% of the PCa and 10.0% of the PSA patients, and the E-cd expression was significantly lower in the former than in the latter (P < 0.05). The abnormal expressions of E-cd in the PCa patients with metastasis, non-metastasis, Gleason score < or = 7 and > 7 were 85.0, 87.5, 100.0 and 86.7%, respectively, with no significant between-group differences (P > 0.05), those in the PCa patients with PSA < or = 10 and > 10 microg/L were 40.0 and 97.1%, respectively, significantly higher in the former than in the latter (P < 0.05), and those in the PCa patients with and without response to endocrine therapy were 93.8 and 72.7%, respectively, with no significant differences between the two groups (P > 0.05). The alpha-cat protein was abnormally expressed in 93.3% of the PCa and 30.0% of the BPH patients, respectively, and the alpha-cat expression was significantly lower in the former than in the latter (P < 0.05). The abnormal alpha-cat expressions in the PCa patients with metastasis, non-metastasis, Gleason score > 7 and < or = 7 were 90.0, 100.0, 90.0 and 100.0%, respectively, with no significant between-group differences (P > 0.05), those in the PCa patients with PSA < or = 10 and > 10 microg/L were 40.0 and 94.3%, respectively, significantly higher in the former than in the latter (P < 0.05), and those in the PCa patients with and without response to endocrine therapy were 100.0 and 81.8%, respectively, with no significant differences between the two groups (P > 0.05).

CONCLUSIONThe expressions of E-cd and alpha-cat are significantly lower in PCa than in BPH, and they are not associated with cancerous metastasis, but negatively correlated with the PSA level in PCa patients.