Background: Previous study has proven that SIRT4 is downregulated in gastric cancer (GC), but the role of SIRT4 has not been clearly understood. The aim of our work was to explore in detail the function and mechanism of SIRT4 in GC. 
Methods: A total of 86 pairs of GC tumor tissues and adjacent normal tissues were collected, and quantitative real-time polymerase chain reaction and Western blotting analyses were used to determine the expression of SIRT4. 
Results: Our study revealed that the expression of SIRT4 was downregulated in GC tissues and cells. In addition, the low expression of SIRT4 was negatively correlated with tumor size, pathological grade, and lymph node metastasis, which predicted a poor prognosis. Multiple functional experiments, including Cell Counting Kit-8 assay as well as colony formation assay, demonstrated SIRT4 suppressed cell proliferation. Moreover, we found epithelial–mesenchymal transition was regulated by SIRT4, thereby regulating cell migration and invasion. 
Conclusion: Overall, our findings show that SIRT4 serves as a tumor suppressor in GC and might act as a novel biomarker and a therapeutic target of GC.
Keywords: sirtuin 4, proliferation, migration, invasion, epithelial–mesenchymal transition, EMT