MicroRNA-21 in peripheral blood mononuclear cells as a novel biomarker in the diagnosis and prognosis of prostate cancer

OBJECTIVE: To evaluate the effects of microRNA-21 (miR-21) in peripheral blood mononuclear cells (PBMC) in the diagnosis and prognosis of prostate cancer (PCa). METHODS: Proved by pathologic biopsy, 92 patients diagnosed with PCa and also underwent resection operation and 85 patients with benign prostatic hyperplasia (BPH) were selected in this study, as well as 97 healthy volunteers were chosen as the control group. PBMC were extracted to examine the relative expression of miR-21 by real time reverse transcriptase-polymerase chain reaction (RT-PCR). The relative operating characteristic (ROC) curves were drew to analyze the diagnosis value of PCa. The survival function curves were made by Kaplan-Meier method to show the miR-21 expression levels of PCa patients. The Log-rank test was adopted to compare the differences among the different groups. The Cox proportional hazard risk regression analysis was used to screen the independent factors affected the PCa patients. RESULTS: The expression levels of miR-21 in PCa group were increased compared to BPH and control group (P < 0.05). The expression of miR-21 was significantly correlated with the Gleason score, clinical stages, bone metastasis and tumor recurrence (all P < 0.05). ROC curves demonstrated that the area under the curve of PCa and BPH distinguished by the miR-21 were 0.974 and 95% confidence intervals (95% CI) were 0.956 similar to 0.993. The sensitivity and specificity were 93.5% and 92.9%. ROC curves demonstrated that the area under the curve of PCa and control group distinguished by the miR-21 were 0.984 and 95% CI were 0.972 similar to 0.997. The sensitivity and specificity were 94.6% and 92.8%. The results of Kaplan-Meier Method demonstrated that the miR-21 expression levels were related to the prognosis of PCa (all P < 0.05). The results of the COX analysis suggested that the miR-21 expression level, tumor recurrence and bone metastasis could be the independent factors affected the prognosis of PCa patients (all P < 0.05). CONCLUSION: miR-21 is highly expressed in the PCa patients, which could be the molecule biomarker of diagnosis and prognosis of PCa.