ObjectiveTo explore expression, clinical and biological significance of plasma miRNA-196a from patients with advanced gastric cancer.MethodsReal time quantitative RT-PCR (qRT-PCR) method was used to detect the miRNA-196a levels in tissues and plasma from 75 gastric cancer patients and 35 benign gastric lesions controls. Then clinic pathological correlations of plasma miRNA-196a in 75 gastric cancer patients were analyzed. Twenty-five gastric cancer patients were randomized selected from 75 patients, to compare plasma miRNA-196a levels between preoperation and postoperation. Meanwhile, the effect of miRNA-196a on the invasion ability of gastric cancer MGC-803 cell line was observed in vitro.ResultsThe levels of miRNA-196a in both plasma and tissues from 75 gastric cancer patients were significantly increased compared with 35 benign gastric lesions controls (P<0.000 1). Clinic pathological data of 75 gastric cancer patients showed that the expressions of miRNA-196a were significantly up-regulated in gastric cancer patients with serosal invasion (P<0.001), lymph node metastasis (P=0.004), distant metastasis (P<0.001) and late clinical stage (P<0.001). The expression of miRNA-196a in peripheral plasma of patients with gastric cancer was significantly down regulated after operation (P<0.000 1). In vitro, overexpression of miRNA-196a significantly increased the invasion ability of MGC-803 cells (P<0.05), whereas knockdown of endogenous miRNA-196a significantly inhibited the invasion ability of MGC-803 cells (P<0.05).ConclusionsThe expression of miRNA-196a is up-regulated not only in peripheral plasma of patients with gastric cancer, but also with the progression of gastric cancer (serosal invasion, lymph node metastasis and distant metastasis). The up-regulation of miRNA-196a expression in peripheral plasma is mainly due to the release of primary tumor tissue. miRNA-196a is expected to be a prognostic marker and a potential therapeutic target for advanced gastric cancer.