Circulating microRNAs as Potential Diagnostic Biomarkers and Therapeutic Targets in Gastric Cancer: Current Status and Future Perspectives

Gastric cancer is among the leading causes of cancer related death worldwide. Patients with gastric cancer are typically asymptomatic, and diagnosed at late stages, supporting the need for the identification of novel prognostic and diagnostic biomarkers. Recently, microRNAs have emerged as molecular regulators that can play key roles in pathogenesis and progression of different malignancies, including gastric cancer. There is a growing body of evidence showing the aberrant activation of some known circulating miRNAs, e.g. let-7a, miR-21, miR-16, miR-93, miR103, miR-192a s well as tissue specific-miRNAs, e.g. miR-18a, miR-10b, miR-544, miR-195, miR-378, miR-34a, miR-145 in patients affected by gastric cancer, which involved with modulation of gastric-cancer-associated genes. In addition, there are mounting evidences on the value of miRNAs which are detected to be associated with drug-resistance mechanisms; suggesting their modulation as a potential approach to overcome chemo-resistance. Attuned with these facts, in this review we highlight several recent preclinical and clinical studies performed on circulating and tissue-specific miRNAs as promising biomarkers for detection of patients at early stages, prediction of prognosis, and monitoring of the patients in response to therapy.