Circulating miR-337-3p as a novel biomarker for prostate cancer.
5087 Background: Recent studies have demonstrated that the aberrant expression of microRNAs (miRNAs)is related with the development of prostate cancer (PCa). Detection of circulating tumor cells (CTC) may provide diagnostic and prognostic information inPCa. The purpose is identifying circulating miRNAs potentially useful for CTC detection in patients with PCa. Methods: In the first study phase we examined blood levels of 92 miRNAs in 49 patients grouped in pools by risk classification: low-risk 42.8%, intermediate-risk 22.5% and high-risk 34.7% and healthy volunteers (N=10) using SYBR-green-based microARN RT-qPCR arrays (Exiqon). Prostate cancer diagnosis was obtained by transrectalultrasound guided biopsy of 10 cores, PSA and digital rectal examination was done previously. In the second study phase using quantitative real-time polymerase chain reaction (qPCR) by TaqMan Human MicroRNAAssays (Life Technologies), we compared the expression levels of miRNAs in blood samples from 34 patients of low-risk, 31 of intermediate-risk, 18 of high-risk localized disease and 22 healthy volunteers paired by age with cases. Receiver-operator characteristic (ROC) curve was used. Results: Blood samples from patients with low, intermediate, high-risk and healthy controls exhibit distinct circulating miRNA signatures. microRNAsdifferential expressed between risk groups (p<0.01) (low, intermediate and high) and control group: 0microARNs upregulated (MU), 12 MU and 68 MU respectively. Highlight the significantlyoverexpression in the intermediate risk group and maintained at the high-risk of microRNAs: 337-3p[247 PicTar predictions (PTP)], 330-3p (307 PTP) and 218 (551 PTP). Preliminary results of the second study phase showed that the median level of miRNA,337-3p was significantly higher in patients with high-risk than that in healthy controls (p=.001). ROC curve analyses indicated that this blood miRNA may beuseful for discriminating patients with high-risk from healthy controls (AUC=.724). Conclusions: miRNAs in the circulation are relatively stable, very accessible, low invasive and easily testable biomarkers. Our preliminary promisingresults suggest miR-337-3p as novel stable blood-based marker for PCa detection.