Correlative studies on uPA mRNA and uPAR mRNA expression with vascular endothelial growth factor, microvessel density, progression and survival time of patients with gastric cancer

AIM: To investigate the correlations between the expression of urokinase-type plasminogen activator (uPA) mRNA, uPA receptor (uPAR) mRNA and vascular endothelial growth factor (VEGF) protein and clinicopathologic features, microvessel density (MVD) and survival time. METHODS: In situ hybridization and immuno-histochemistry techniques were used to study the expressions of uPA mRNA, uPAR mRNA, VEGF and CD34 protein in 105 gastric carcinoma specimens. RESULTS: Expressions of uPA mRNA, uPAR mRNA and VEGF protein were observed in 61 (58.1%) cases, 70 (66.7%) cases and 67 (63.8%) cases, respectively. The uPA mRNA and uPAR mRNA positive expression rates in infiltrating-type cases (73.7%, 75.4%), stage III-IV (72.1%, 75.4%), vessel invasion (63.2%, 69.9%), lymphatic metastasis (67.1%, 74.4%) and distant metastasis (88.1%, 85.7%) were significantly higher than those of the expanding-type (chi2 = 15.57, P = 0.001; chi2 = 6.91, P = 0.046), stage I-II (chi2 = 19.22, P = 0.001; chi2 = 16.75, P = 0.001), non-vessel invasion (chi2 = 11.92, P = 0.006; chi2 = 14.15, P = 0.002), non-lymphatic metastasis (chi2 = 28.41, P = 0.001; chi2 = 22.5, P = 0.005) and non-distant metastasis (chi2 = 12.32, P = 0.004; chi2 = 17.42, P = 0.002; chi2 = 11.25, P = 0.012; chi2 = 18.12, P = 0.002).The VEGF positive expression rates in infiltrating-type cases (75.4%), stage III-IV (88.5%), vessel invasion (82.9%), lymphatic metastasis (84.3%) and distant metastasis (95.2%) were significantly higher than those of the expanding-type (chi2 = 9.61, P = 0.021), stage I-II (chi2 = 16.66, P = 0.001), non-vessel invasion (chi2 = 29.38, P = 0.001), non-lymphatic metastasis (chi2 = 18.68, P = 0.005), and non-distant metastasis (chi2 = 22.72, P = 0.007; chi2 = 21.62, P = 0.004). The mean MVD in the specimens positive for the uPA mRNA, uPAR mRNA and VEGF protein was markedly higher than those with negative expression groups. Moreover, a positive relation between MVD and uPA mRNA (rs = 0.199, P = 0.042), uPAR mRNA (rs = 0.278, P = 0.035), and VEGF (rs = 0.398, P = 0.048) expressions was observed. The mean survival time in cases with positive uPA mRNA, uPAR mRNA and VEGF protein expression or MVD value > or = 54.9 was significantly shorter than those in cases with negative expression or MVD value < 54.9. CONCLUSION: uPA and uPAR expressions are correlated with enhanced VEGF-induced tumor angiogenesis and may play a role in invasion and nodal metastasis of gastric carcinoma, thereby serving as prognostic markers of gastric cancer.