['Gastric cancer (GC) is a common malignant disease and microRNAs (miRNAs) have been shown to play important roles in GC tumorigenesis. As the clinical outcome of GC is closely correlated with the clinical stage at the time of diagnosis, early detection and prevention are crucial. This study was designed to evaluate the expression level of plasma miR-23b in patients with GC and investigate the relationship between plasma miR-23b expression level and the prognosis of GC.', 'We recruited 138 patients diagnosed with GC and 50 healthy volunteers. Quantitative real-time PCR (qRT-PCR) was performed to evaluate the expression level of plasma miR-23b in all participants. The association between miR-23b expression and clinicopathological factors as well as survival rates was analyzed. Receiver operator curve (ROC) analysis was carried out to evaluate the diagnostic performance of plasma miR-23b for GC.Univariate and multivariate Cox regression analyses were conducted to determine whether plasma miR-23b was an independent predictor of survival.', 'The expression levels of miR-23b were upregulated in plasma samples from GC patients (P<0.01) and were significantly associated with T stage, distant metastasis, and differentiation. Significantly shorter 5-year overall survival (OS) and disease-free survival (DFS) were observed in patients with higher expression of the miR-23b (P<0.01). The area under the curve (AUC) of high expression of plasma miR-23b to diagnose GC was 0.80 (95% CI: 0.74-0.86, P<0.001). Multivariate analysis revealed that enhanced expression of plasma miR-23b was an independent predictor of OS (P=0.015) and DFS (P=0.004).'] Is up-Regulation of Plasma miR-23b Associated with Poor Prognosis of Gastric Cancer?