Abstract: Objective To investigate the regulatory mechanism and significance of chemokine IL-8 in epithelial mesenchymal transition (EMT) leading to gastric cancer. Methods Western blot, enzyme-linked immunosorbent assay (ELISA) and other techniques were used to detect the expression levels of IL-8 and EMT-related genes (E-cadherin, vimentin, twist, etc.) in gastric cancer tissues and plasma. To study the correlation between IL-8 and EMT in gastric cancer cells with MGC-803. Results The expression level of IL-8 in tumor tissues (710.53±89.92) was significantly higher than that in adjacent tissues (510.52±85.45), and the difference was statistically significant (P<0.001). Compared to normal tissue，the expression rates of IL-8, Twist and vimentin in gastric cancer tissues were significantly higher than those in normal gastric mucosa tissues（P<0.05）, while the expression rates of E-cadherin in gastric cancer tissues were lower than those in normal tissues（P<0.05).The secretion of IL-8 was positively correlated with Twist protein (P < 0.001), vimentin protein (r=0.454, P< 0.001), and negatively correlated with E-cadherin protein (P< 0.001). Conclusion The expression of chemokine IL-8 is increased in gastric cancer tissues, and its expression level is correlated with the expression of EMT-related proteins, which indicates that IL-8 is related to the invasion and metastasis of gastric cancer. Meanwhile, the expression of IL-8 may also be used as one of the criteria in the prognosis of patients, for the invasion and metastasis of gastric cancer.

Key words: gastric cancer, IL-8, epithelial-mesenchymal transition, invasion and metastasis