Prognostic implications of tissue and serum levels of microRNA-128 in human prostate cancer.

BACKGROUND AND PURPOSE MicroRNA-128 (miR-128) has been identified as a negative regulator of malignant phenotypes of prostate cancer (PCa) cells. The aim of this study was to evaluate the prognostic implications of both tissue and serum levels of miR-128 expression in PCa patients undergoing radical prostatectomy. METHODS A series of 128 cases with PCa were evaluated for both tissue and serum levels of miR-128 expression by quantitative reverse-transcription PCR. RESULTS Compared with non-cancerous prostate tissues and normal sera, both tissue and serum levels of miR-128 expression were significantly decreased in PCa patients (both P<0.001). Importantly, there was a close correlation between tissue and serum levels of miR-128 expression in PCa patients (rs=0.808, P<0.001). Then, low miR-128 expression in both PCa tissues and patients' sera were dramatically associated with aggressive clinicopathological features, including advanced pathological stage (both P=0.001), positive lymph node metastasis (P=0.006 and 0.01, respectively), high preoperative PSA (both P=0.01) and positive angiolymphatic invasion (both P=0.02). Moreover, Kaplan-Meier survival analysis showed that low miR-128 expression in both PCa tissues and patients' sera were significantly associated with short biochemical recurrence (BCR)-free survival. Furthermore, multivariate analysis indicated that both tissue and serum levels of miR-128 expression were independent prognostic factors for BCR-free survival of PCa patients. CONCLUSION Our data suggest that the decreased expression of miR-128 in both tissue and serum samples of PCa patients may be associated with tumor malignant progression and BCR-free survival. Particularly, serum miR-128 may be developed as a novel noninvasive biomarker for PCa diagnosis and prognosis.