Abstract: Background and purpose: miR-124 is considered to be a tumor suppressor in multiple tumors, including lung cancer, prostate cancer, bladder cancer, and breast cancer. However, its function is unclear in gastric cancer. This study aimed to explore the expression of miR-124 in human gastric mucosal epithelium cells and different gastric cancer cells, as well as gastric cancer tissues and matched para-cancerous tissues. The correlations of miR-124 expression with gender, age, histological grade, T stage, TNM stage, lymph node metastasis and prognosis of gastric cancer patients were analyzed. Methods: A real-time fluorescent quantitative polymerase chain reaction (RTFQ-PCR) was employed for detecting the expression of miR-124 in human gastric mucosal epithelium cells and gastric cancer cells. The expression of miR-124 in gastric cancer tissues and matched para-cancerous tissues was detected by in situ hybridization. Results: The RTFQ-PCR results indicated that the expression of miR-124 was down-regulated in MKN-74, MKN-28, MKN-45, MGC-803, SGC-7901 and AGS cells compared to GES-1 cells. In situ hybridization showed that miR-124 was strongly expressed in normal gastric mucosa. However, low expression, focal positive expression or lack of miR-124 expression were observed in gastric cancer tissues. Statistical analysis showed that miR-124 was closely correlated to histological stage, TNM stage and node metastasis of gastric cancer patients, but not the age, gender and tumor size. The OS and DFS of the patients with low expression of miR-124 were shorter than that of the patients with high expression of miR-124. Multivariate analysis suggested that miR-124 down-regulation was an independent prog-nostic factor for survival in patients with gastric cancer. Conclusion: miR-124 is down-regulated in gastric cancer cells and tissues. The expression of miR-124 is correlated to histological stage, TNM stage, node metastasis and prognosis.

Key words: Gastric cancer, miR-124, Clinical significance, In situ hybridization