Circulating miRNAs as Potential Biomarkers in Prostate Cancer Patients Undergoing Radiotherapy

Introduction: Disease recurrence is a major concern in patients with localized prostate cancer (PCa) following treatment with radiotherapy (RT), and few studies have evaluated the clinical relevance of microRNAs (miRNAs) prior and post-RT. Purpose: We aimed to investigate the significance of miRNAs in the outcomes of prostate cancer patients undergoing radiotherapy and to identify the related pathways through bioinformatics analysis. Materials and Methods: The expression levels of miR-21, miR-106b, miR-141 and miR375 involved in the response to radiotherapy were assessed by RT-qPCR in the serum of PCa patients (n=56) prior-and post-RT. Results: Low expression levels of miR-106b prior-RT were associated with extracapsular extension and seminal vesicles invasion by the tumor (p=0.031 and 0.044, respectively). In the high-risk subgroup (n=47), post-RT expression levels of miR-21 were higher in patients with biochemical relapse (BR) compared to non-relapse (p=0.043). Also, in the salvage treatment subgroup (post-operative BR; n=20), post-RT expression levels of miR-21 and miR-106b were higher in patients with BR compared to non-relapse (p=0.043 and p=0.032, respectively). In the whole group of patients, high expression levels of miR-21 prior-RT and of miR-106b post-RT were associated with significantly shorter overall survival (OS; p=0.049 and p=0.050, respectively). No associations were observed among miR-141 and miR-375 expression levels with clinicopathological features or treatment outcome. Bioinformatics analysis revealed significant enrichment in DNA damage response pathways. Conclusion: Circulating miRNAs prior or post-RT may hold prognostic implications in patients with PCa.

Automated summary

The study found that circulating miRNAs prior to or after radiotherapy may have prognostic implications in prostate cancer patients. Specific miRNA expression levels were associated with patients' pathological features and treatment outcomes, and were also linked to DNA damage response pathways.