In previous studies, we demonstrated the significant role of microRNA-449a (miR-449a) in colorectal cancer with in vivo and clinical samples. The importance of miR-449a in gastric cancer is still to be elucidated. This study examined the impact of miR-449a expression in tumor tissue and serum and investigated its potential as a prognostic marker in gastric cancer.

Sixty-six patients with gastric cancer who underwent surgery were included in the study. miR-449a expression in tumor tissue and serum were investigated by real-time polymerase chain reaction analysis. The association of miR-449a expression with clinicopathological factors and patient prognosis were also investigated.

miR-449a expression was lower in tumor tissue than non-tumor tissue. miR-449a in tumor tissue negatively correlated with the malignancy of tumor and clinical stage. Increased carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) levels were seen at significantly higher frequencies in patients with low miR-449a expression. Patients with low miR-449a expression had poorer cancer-specific survival compared to those with high miR-449a expression. The univariate analysis showed that lymphovascular invasion, increased CEA and CA19-9 and a low expression of miR-449a were associated with a poorer 5-year cancer-specific survival. miR-449a expression level in serum correlated to that in tumor tissue and was also associated with tumor malignancy.

The miR-449a level in tumor tissue might be useful as a prognostic indicator for patients with gastric cancer and miR-449a in serum appears to reflect its expression in tumor tissue.