Expression of serum exosomal miRNA-21 and its clinical significance in gastric cancer

Objective To explore the relationship of serum exosomal miRNA-21 expression and clinical pathological parameters and prognosis in gastric cancer (GC) patients. Methods Exosomes from serum samples of 52 GC patients and 10 healthy controls were extracted using the ExoQuick Exosome Precipitation Solution, and were further validated by immunoblotting for exosome markers and characterization of nanoparticle using NanoSight. The expression levels of exosomal miRNA-21 in exosomes was detected by RT-qPCR, and its relationship with clinicopathological features and prognosis was further analyzed. Results The expression level of miRNA-21 in serum exosomes of patients with GC was significantly higher than that of normal subjects (2.59±0.12 vs. 1.16±0.10, t=5.168, P<0.05), and its high expression was significantly related to tumor grade, depth of invasion, lymph node metastasis, distant metastasis, vascular invasion, nerve invasion and TNM stage (all P<0.05). Patients in exosomal miRNA-21 high expression group had lower overall survival than that of exosomal miRNA-21 low expression group (χ2=14.573, P<0.05). Multivariate analysis using the COX regression test identified that higher serum exosomal miRNA-21 was an independent predictor of mortality for GC patients (HR=2.863, 95%CI: 1.063-7.712, P=0.038). Conclusion The expression of miRNA-21 in serum exosomes of GC patients is up-regulated, and its high expression is associated with multiple unfavorable clinicopathological factors and poor prognosis of patients. Key words: Stomach neoplasms; Exosomes; MicroRNAs; Pathology , clinical; Prognosis