Evaluating the expression level of miR-9-5p and miR-192-5p in gastrointestinal cancer: introducing novel screening biomarkers for patients.

OBJECTIVE: It has been indicated that there is a tight association between cancer and different factors, such as environment and genetics, including aberrantly expressed microRNAs. The crucial role of microRNAs in the regulation of diverse signaling pathways in gastrointestinal cancer has been established in several studies. In this study, we aimed to evaluate the expression of microRNA-9 and -192 in colon and gastric cancers. After extracting the RNA from tissues and serum samples of patients, suffering from colon and gastric cancer, cDNA was synthesized. Then by performing quantitative real-time PCR, we evaluated the expression level of miR-9-5p and miR-192-5p in collected samples. RESULTS: Unlike to colon cancer in which the expression level of miR-9-5p remained unchanged, the relative expression of this miRNA decreased remarkably in gastric cancer (with P value < 0.05), in comparison with normal adjacent tissues. In agreement with this finding, we also found that the expression level of miR-192-5p was decreased in gastric cancer tissues, compared to normal gastric tissue. Given the reduction in the expression level of miR-9-5p and miR-192-5p in gastric cancer, it could be postulated to consider these miRNAs as promising diagnostic biomarkers.