Circulating MicroRNAs: Valuable Biomarkers for the Diagnosis and Prognosis of Gastric Cancer

Background: Gastric cancer is a malignancy with high mortality rate worldwide. Poor clinical symptoms, unfavorable prognosis and absence of proper diagnostic techniques for early detection cause death in many patients. Presence of new sensitive and specific biomarkers for early detection and progression of GC could lead to reduction in the mortality rate. In addition to intracellular miRNAs, circulating miRNAs reflect the state of cancer progression and might be potential biomarkers for rapid detection and also therapy in GC. Objective: After giving a brief explanation about circulating miRNAs and their various types, we then reviewed comprehensively the last studies which investigated circulating miRNAs as diagnostic/prognostic biomarkers in GC. Methods: Research and review articles in PubMed and Scopus databases were summarized. Keywords mainly used were in related to circulating miRNAs and their diagnostic and prognostic value in gastric cancer. Among the numerous circulating miRNAs a comparison was made based on their repeatability, specificity and sensitivity. Results: Comparisons indicated high diagnostic value of circulating miRNAs in comparison with other detection methods based on their high sensitivity and specificity. There was also a relation between altered expression level of large number of circulating miRNAs and clinicopathological factors and also response to therapy in GC. Conclusion: Several advantages of circulating miRNAs as detection biomarker have led to extensive studies and significant advances. Altered expression pattern of circulating miRNAs have correlation with pathological status of GC tissues and their exclusive features make them ideal early diagnostic, prognostic and predictive biomarkers for GC.