Down-regulated serum miR-126 is associated with aggressive progression and poor prognosis of gastric cancer

BACKGROUND: miR-126 functions as a tumor suppressor in gastric cancer (GC), however, the clinical significance of serum miR-126 in GC remains unclear. OBJECTIVE: To investigate the associations of serum miR-126 level with the clinicopathological characteristics and prognosis of GC patients. METHODS: Quantitative real-time polymerase chain reaction was performed to examine the expression levels of miR-126 in 338 GC patients' tissues and sera, and 50 healthy controls' sera. The associations of serum miR-126 with clinicopathological characteristics and clinical outcome were evaluated. RESULTS: Compared with the matched adjacent non-tumor tissues and normal sera, miR-126 expression was significantly down-regulated in both tumor tissues and sera of GC patients. Importantly, there was a positive correlation between tissue and serum levels of miR-126 in GC patients. A reduced serum miR-126 level statistically correlated with aggressive clinicopathological characteristics, such as larger tumor size, deeper local invasion, more lymph node metastasis, advanced TNM stage, and poorer prognosis. Notably, multivariate analysis identified reduced serum miR-126 level as an independent predictor for the unfavorable prognosis of GC. CONCLUSIONS: These results indicate for the first time that serum miR-126 may serve as a novel prognostic biomarker in GC.