Identification of diagnostic utility and molecular mechanisms of circulating miR-551b-5p in gastric cancer

Background: Gastric cancer (GC) is one of the most common cancers globally leading to 850,000 deaths each year. GC patients are often diagnosed at advanced stages which results in poor prognosis. This study aimed to identify a novel circulating miRNA as the diagnostic biomarker of GC and further explore its regulatory mechanisms in GC. Materials and methods: First, the candidate serum miRNA was selected after analysis of microarray data. Then, the levels of candidate miRNA in the serum of GC patients were validated in an independent cohort. The diagnostic utility of miRNA was evaluated by using receiver operating characteristic curve (ROC) analysis. The functional and pathways enrichment analysis of targets of" candidate miRNA were explored by online tool DAVID. Results: After comprehensive analysis of Gene Expression Omnibus (GEO) dataset, miR-551b-5p was selected as candidate due to its highest differential fold-change. Another independent cohort showed that serum miR-551b-5p could differentiate GC patients from healthy controls (HCs) with area under the curve (AUC) of 0.84 (95%CI: 0.75-0.93). The functional and pathways enrichment analysis revealed that targets of miR-551b-5p mainly located in cytoplasm and significantly associated with regulation of ubiquitin-dependent protein catabolic process, cell division, and mRNA stability. Conclusions: Circulating miR-551b-5p was a novel promising biomarker for the detection of GC and exploration of the molecular mechanisms of miR-551b-5p is useful to search for new therapeutic strategies of GC.