Expression And Clinical Significance Of Claudin-4 And MMP-9 In Gastric Cancer

Tight junctions(TJ) are important intercellular junctional complexes and Claudins are the most important tight junction scaffolding proteins which determine the functions of TJ. Among them, Claudin-4 is closely related with gastric cancer. As a matrix metalloproteinase(MMPs), matrix metalloproteinase-9 (MMP-9) degrades basement membranes and extracellular matrix components, thereby promoting tumor invasion, metastasis and interstitial angiogenesis. There is few literature about the relationship between the expression of Claudin-4,MMP-9 and the clinicopathological significance of gastric cancer and the relationship between Claudin-4 and MMP-9 in gastric cancer.To discuss the expression and clinicopathological significance of Claudin-4 and MMP-9 as well as their correlation in human gastric cancer, 68 tissue specimens of gastric cancer were collected from September 2007 to September 2009, Of which 20 cases made into paraffin sections and fresh frozen specimens were stored. Then, expression of Claudin-4,MMP-9 proteins and mRNA were detected in gastric cancer tissues and normal gastric tissues by immunohistochemical staining and real time quantitative PCR respectively. Claudin-4 and MMP-9 proteins in gastric cancer tissues by immunohistochemistry were detected in the left 48 tissue specimens which were only made into paraffin sections .The relationship between the expression of claudin-4 and MMP-9 and clinicopathological parameters were analysed.Results shows that the expression of Claudin-4 in gastric cancer tissues of intestinal-type and Borrmann type I and II was significantly higher than that in diffuse type and Borrmann type III and IV respectively(P <0.05),Claudin-4 expression was correlated with cell differentiation of gastric cancer, the worse differentiation of gastric cancer, the lower expression of Claudin-4(P <0.05).On the contrary,MMP-9 expression in gastric cancer tissues of intestinal-type and Borrmann type I and II was significantly lower than that in diffuse type and Borrmann type III and IV respectively(P <0.05);MMP-9 expression was correlated with cell differentiation of gastric cancer, the worse differentiation of gastric cancer, the higher expression of MMP-9(P <0.05) . The expression of Claudin-4,MMP-9 in gastric cancer tissues was significantly higher than normal gastric foveolar epithelial tissues(P <0.05), and the correlation between expression of Claudin-4 and MMP-9 was also found(P <0.05). The expression of Claudin-4 and MMP-9 are correlated with the incidence and the biological behavior of gastric cancer and could be used to predict the biological behavior of gastric cancer.