MicroRNAs (miRNAs) are a group of small non coding RNAs, which play a crucial role in Gastric Cancer (GC). miRNAs produce dual, opposite effects through target gene mRNA, namely tumor suppressor genes (TS-miRs) or oncogenes (oncomiRs). In general, carcinogenic miRNAs are overexpressed in GC and can inhibit tumor suppressor genes. On the contrary, the expression of tumor suppressor miRNAs is down regulated in GC, which leads to the development of cancer. Aberrantly expressed miRNAs, as tumor suppressor genes or oncogenes, participate in the occurrence and development of GC and regulate different phenotypes, such as proliferation, apoptosis, invasion, metastasis and drug resistance. In addition, miRNAs can also be used for the diagnosis and prognosis
of GC. This article reviews the role of miRNAs in the occurrence and development of GC, and the potential application of miRNAs in diagnosis and prognosis.