Circulating Pre-microRNA-488 in Blood Is a Potential Prognostic Biomarker in Gastric Cancer.

[BACKGROUND/AIM] MicroRNAs (miRNAs) have been highlighted as non-invasive clinical biomarkers in liquid biopsy. This study aimed to investigate the clinical significance of circulating tumor suppressors, precursor-miR-488 (pre-miR-488) and miR-488-5p, in the blood of patients with gastric cancer (GC).

[MATERIALS AND METHODS] The expression levels of pre-miR-488 and miR-488-5p in tumor tissues and blood were measured using RT-qPCR, and the clinicopathological and prognostic significance of their expression was assessed in patients with GC. Next, pathway analysis of miR-488-5p expression in GC tissues was performed by gene set enrichment analysis (GSEA) using the TCGA dataset. Finally, pre-miR-488 in exosomes from the plasma of GC patients was analyzed using RT-qPCR.

[RESULTS] Both pre-miR-488 and miR-488-5p were down-regulated in tumor tissues, whereas their expression in the blood was significantly higher in patients with GC than in healthy controls. Low expression of pre-miR-488 or miR-488-5p in the blood was associated with poor prognosis in patients with GC. Furthermore, low pre-miR-488 expression in the blood was an independent poor prognostic factor for overall survival. miR-488-5p expression tended to be negatively correlated with the expression of gene sets involved in epithelial-mesenchymal transition and hypoxia. pre-miR-488 was detected in exosomes isolated from the plasma of patients with GC.

[CONCLUSION] Circulating pre-miR-488 and miR-488-5p expression in the blood may serve as novel prognostic biomarkers for patients with GC, predicting clinical outcomes and guiding therapeutic strategies.