Abstract
Prostate cancer (PCa) is one of the most common malignancies in men worldwide, yet early detection and accurate risk stratification remain challenging. MicroRNAs (miRNAs), key post-transcriptional regulators, have emerged as promising minimally invasive PCa biomarkers. Accumulating evidence suggests that the relative abundance of the 3p and 5p miRNA mature strands is not fixed but dynamically shaped by the cellular context. Therefore, dual-arm profiling followed by analysis of 3p/5p ratios may distinguish disease states and stages more effectively than evaluating the canonical strand alone. In this pilot, single centre case-control study, we used RT-qPCR with synthetic RNA-based calibration curves to quantify the expression levels and strand ratios of hsa-miR-130a and hsa-miR-365a in plasma and urine of PCa patients and assessed their diagnostic value and association with the disease. Our results revealed concordant downregulation of hsa-miR-130a-3p in PCa in both fluids, accompanied by significant alterations in 3p/5p ratios, suggesting dysregulation of miRNA processing or strand selection. Similarly, only hsa-miR-365a-3p was significantly reduced in patient urine, whereas hsa-miR-365a-5p showed strong correlations with clinical markers such as prostate specific antigen (PSA) and PSA density. These findings, supported by public expression data, highlight the tissue- and fluid-specific selection of miRNA strands, highlight the potential of dual-arm profiling for a more nuanced, non-invasive PCa diagnostics and warrant validation in a larger, multi-centre cohort.