miRNAs expression profiles and the clinical significance of miR-21 expression in human gastric cancer tissues

OBJECTIVE:To study miRNAs expression profile and explore miR-21 expression and its clinicopathological significance in human gastric cancer tissues.METHOD: Sixty-five pairs of fresh gastric cancer tissues and corresponding normal gastric epithelium were collected.Six of them were randomly selected and miRNA microarray were applied.Quantitative real-time PCR were used to validate the reliability of chips and detect the expression of miR-21 in sixty-five cases of gastric cancer tissues and corresponding normal gastric tissues.RESULTS:Compared with normal gastric tissues,7 miRNAs(miR-374b*,miRPlus-E1212,miR-338-5p,miR-297,miR-21,miR-135b and miR-18a) were significantly upregulated more than 2 folds,9 miRNAs(miR-29b-2*,miR-1260,miRPlus-E1241,miR-S1-5p,miR-148a,miR-29c,miR-647,miR-196b*,ebv-miR-BART5) were significantly downreguated more than 2 folds in gastric cancer tissues.The results of microarray were verified by quantitative real-time PCR.MiR-21 expression was significantly higher in most of gastric cancer tissues compared with corresponding epithelial tissues(46/65,70.8%).Its high expression was related to tumor differentiation(χ2=6.257,P=0.012),invasion(χ2=5.705,P=0.017) and lymphnode metastasis(χ2=7.107,P=0.008).CONCLUSIONS: Differential expressed miRNAs may be involved in gastric cancer and provides a new basis for research about development mechanism of gastric cancer;miR-21 is closely related to biological behavior of human gastric cancer,it could be an indicator in diagnosis and treament of human gastric cancer.