Background: miR-4262 was identified as a tumor promoter in several cancers, but its exact role in gastric carcinoma is still largely unknown. 
Methods: The expression of miR-4262 was detected in gastric cancer tissues. Different concentrations of miR-4262 mimic and miR-4262 antagomir were respectively transfected into primary gastric carcinoma cells. After incubation for 72 h, the overexpression efficiencies were confirmed by qPCR, cell proliferation was detected with the CCK-8 assay, cell apoptosis was detected by using the PI/Annexin V Cell Apoptosis Kit, and cell invasion was detected with the Transwell invasion assay. The molecular mechanisms underlying the action of miR-4262 in gastric carcinoma cells were also explored. 
Results: In this study, we found that miR-4262 was significantly downregulated in gastric tissue from gastric cancer patients compared with that from the control group. Moreover, the level of miR-4262 was significantly lower in advanced gastric carcinoma. Additionally, lower level of miR-4262 was correlated with poorer prognosis and lower survival rate in gastric cancer patients. Then, different concentrations of miR-4262 mimic and miR-4262 antagomir were transfected into primary gastric carcinoma cells, respectively. The results showed that miR-4262 mimic suppressed proliferation and invasion and promoted cell apoptosis in a dose-dependent manner in gastric carcinoma cells. In contrast, miR-4262 antagomir increased proliferation and invasion and decreased cell apoptosis in a dose-dependent manner in gastric carcinoma cells. Furthermore, miR-4262 could directly target and suppress the expression of the proto-oncogene CD163.
Conclusion: Our findings indicate that lower level of miR-4262 predicts poorer prognosis in gastric patients, and miR-4262 can target proto-oncogene CD163 to suppress gastric cancer cell proliferation and invasion.
Keywords: miR-4262, gastric carcinoma, prognosis, proliferation and invasion, CD163