Altered expression profile of micrornas in gastric stromal tumor

MicroRNAs (miRNAs) play important roles in carcinogenesis, but the global miRNA expression profile in gastric stromal tumor tissues remains unclear. This study was to examine the miRNA expression profile in gastric stromal tumor tissues and explore the function of dysregulated miRNAs by performing gene ontology (GO) and pathway enrichment analysis. Total RNA was extracted and purified from 3 pairs of frozen gastric stromal tumor tissues and the adjacent non-tumor tissues by using mirVana™ miRNA isolation kit. The miRNA expression was analyzed with Affymetrix microarrays (version 4.0) containing 2578 human mature microRNA probes. The dysregulated microRNAs were validated by quantitative RT-PCR in 30 pairs of gastric stromal tumor tissues. The target gene of the dysregulated microRNAs was predicted by miRanda, TargetScan and PicTar. GO and pathway enrichment analysis was conducted to examine the potential function of miR-3178 and miR-193a-5p. The results showed that there were 12 differently expressed microRNAs in gastric stromal tumor tissues, among which 10 miRNAs were down-regulated, and 2 were up-regulated (P<0.05). The validation results by RT-PCR were in accordance with those by microRNA microarry. GO analysis found that the target genes of miR-3178 were involved in 5 GO terms and those of miR-193a-5p in 7 GO terms in level 2. Pathway enrichment analysis suggested that miR-3178 and miR-193a-5p were related to 57 and 122 signaling pathways, respectively. It was concluded that gastric stromal tumor displays a unique miRNA signature. This specific expression may become a new diagnostic and prognostic biomarker for gastric stromal tumor. miR-3178 and miR-193a-5p function as suppressive microRNAs, and they may also become diagnosis and treatment targets for gastric stromal tumor.