Low expression levels of plasma miR-141 are associated with susceptibility to gastric cancer

MicroRNAs (miRNAs/miRs) offer great potential as biomarkers for the early detection and prognosis of cancer, and the discovery of miRNAs associated with gastric cancer is required. In the present study, the differences in the plasma expression levels of miR-141 between patients with gastric cancer and healthy controls, and the role of miR-141 in gastric cancer cell oncogenesis were investigated. A follow-up study of 164 patients with gastric cancer who underwent tumor resection was conducted, and comparisons with healthy control subjects were drawn. To investigate the biological functions of miR-141, a series of in vitro and in vivo assays were conducted, including proliferation, wound-healing and Transwell assays, and a xenograft tumor model. The results demonstrated that miR-141 expression was significantly decreased in tumor tissues compared with in healthy tissues (P<0.05). Kaplan-Meier analysis revealed improved survival benefits with increased miR-141 expression (as determined using the log-rank test, P<0.001), and multivariate Cox regression analysis revealed that patients with decreased expression levels of miR-141 carried a greater risk of death (hazard ratio=2.352; 95% CI=1.379–4.012; P=0.002). The downregulation of miR-141 was also associated with WHO staging, particularly for lymph node and distant metastasis. Exogenous overexpression of miR-141 significantly inhibited the proliferative and migratory abilities of the gastric cancer cell line BGC-823. In vivo studies also demonstrated that exogenous overexpression of miR-141 in BGC-823 cells markedly reduced tumor growth in nude mice. The present study revealed that increased miR-141 expression may be a positive prognostic factor, which may be clinically beneficial in patients with gastric cancer.