Association of microRNA-126 expression with clinicopathological features and the risk of biochemical recurrence in prostate cancer patients undergoing radical prostatectomy

Objective: Numerous studies have suggested that microRNA-126 (miR-126) is involved in development of various cancer types as well as in malignant proliferation and invasion. However, its role in human prostate cancer (PCa) is still unclear. The aim of this study was to investigate miR-126 expression in PCa and its prognostic value for PCa patients undergoing radical prostatectomy. Methods: A series of 128 cases with PCa were evaluated for the expression levels of miR-126 by quantitative reverse-transcription PCR (qRT-PCR). Kaplan-Meier analysis and Cox proportional hazards regression models were used to investigate the correlation between miR-126 expression and prognosis of PCa patients. Results: Compared with non-cancerous prostate tissues, the expression level of miR-126 was significantly decreased in PCa tissues (PCa vs. non-cancerous prostate: 1.05 +/- 0.63 vs. 2.92 +/- 0.98, P < 0.001). Additionally, the loss of miR-126 expression was dramatically associated with aggressive clinical pathological features, including advanced pathological stage (P = 0.001), positive lymph node metastasis (P = 0.006), high preoperative PSA (P = 0.003) and positive angiolymphatic invasion (P = 0.001). Moreover, Kaplan-Meier survival analysis showed that PCa patients with low miR-126 expression have shorter biochemical recurrence (BCR)-free survival than those with high miR-126 expression. Furthermore, multivariate analysis indicated that miR-126 expression was an independent prognostic factor for BCR-free survival after radical prostatectomy. Conclusion: These findings suggest for the first time that the loss of miR-126 expression may play a positive role in the malignant progression of PCa. More importantly, the downregulation of miR-126 may serve as an independent predictor of BCR-free survival in patients with PCa. Virtual slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1740080792113255.