Gastric cancer (GC) is the most prevalent malignancy worldwide and a common cause of death in Iran. Studies have proved that a variety of dysregulated microRNAs is involved in the development and progression of gastric cancer. The present study aimed to evaluate the expression levels of plasma circulating oncogenic miR-21 and miR-192 and their association with clinical phenotypes of patients with gastric cancer in the north of Iran. Material and Methods: Clinico-pathological analysis was

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... ed using a standard protocol and pathological tests. The expression levels of miR-21 and miR-192 were measured using quantitative reverse transcription-polymerase chain reaction in the plasma of twenty pre/post-operative gastric cancer patients and twenty healthy subjects. The receiver operating characteristic (ROC) curve of these microRNAs was analyzed to investigate their diagnosis properties. Results: The study results indicated that plasma miR-21 expression was significantly associated with tumor stage and helicobacter pylori infection status (P=0.024, P=0.0004, respectively). However, no association was observed between clinic-pathological characteristics and miR-192 expression. The results showed that the plasma levels of miR-21 (P=0.0001) and miR-192 (P=0.0007) were significantly higher in GC patients compared to those in healthy individuals. Furthermore, the ROC analyses yielded the area under the curve (AUC) values of 0.9525±0.03 (P<0.0001) and 0.5925±0.09 (P=0.316) for miR-21and miR-192, respectively. Pearson regression analysis showed that there was no significant correlation between the expression of miR-21 and miR-192 (P=0.1507). Conclusion: Based on the obtained results, the expression of the plasma level of miR-21 was significantly higher in gastric cancer patients compared to that in the healthy group. Furthermore, the higher levels of AUC in miR-21 indicated the potential role of miR-21 as a noninvasive biomarker for the prognosis of gastric cancer in the population of the north of Iran.