RABEX-5 overexpression in gastric cancer is correlated with elevated MMP-9 level.

OBJECTIVE

This study aimed to investigate mRNA and protein expression levels of RABEX-5 and matrix metalloproteinase-9 (MMP-9), their mutual correlation, and biological behavior in gastric cancer (GC) patients.

METHODS

The expression levels of RABEX-5 and MMP-9 were determined by real-time quantitative PCR and Western blotting in cell lines, GC tissues, and adjacent normal tissues. In addition, RABEX-5 and MMP-9 expression was analyzed by immunohistochemistry in formalin-fixed tissues from 113 GC patients.

RESULTS

The mRNA and protein expression levels of RABEX-5 and MMP-9 in GC cell lines and GC tissues were higher than those in normal gastric mucosa cell line and adjacent normal tissues. RABEX-5 expression and MMP-9 expression in GC tissues were significantly and positively correlated. In addition, the size of tumor (p<0.001), Lauren's classification (p=0.009), and N stage (p<0.001) were identified as the relative factors of RABEX-5 expression, whereas the expression of MMP-9 was correlated with N stage (p=0.003). The results of the multivariate analysis revealed that the independent predictive factors of overall survival were T stage (hazard ratio (HR)=2.382; p=0.028), N stage (HR=1.755; p<0.001), RABEX-5 expression (HR=0.452; p=0.004), and MMP-9 expression (HR=0.561; p=0.032).

CONCLUSIONS

RABEX-5 and MMP-9 expression levels were elevated in GC tissues and were associated with tumor invasion, metastasis, and prognosis. Therefore, they may be promising prognostic indicators of survival in GC patients.