Significance of vascular endothelial growth factor expression and its correlation with inducible nitric oxide synthase in gastric cancer

AIM:To investigate the clinical significance of theexpression of VEGF165mRNA and the correlation withvascular endothelial growth factor (VEGF) protein andinducible nitric oxide synthase (iNO) in human gastriccancer.METHODS:We tested VEGF165mRNA expression in 31 casesof resected gastric cancer specimens and normal pairedgastric mucosae by RT-PCR.Total RNA was extracted withTRIzol reagents,transcribed into cDNA with oligo (dT15)priming,inner controlled with β-actin expression andagarose gel isolated after PCR.VEGF expression wasquantitated with IS1000 imaging system.Meanwhile wealso examined expression levels of VEGF protein and iNOSin 85 cases of gastric cancer.All paraffin-embeddedsamples were immunohistochemically stained by streptavidin-peroxidase method (SP).RESULTS:The mean expression of VEGF165mRNA ingastric cancer was 1.125±0.356,significantly higher thanthat of normal paired mucosae,which was 0.7604±0.278.The data indicated that the expression level ofVEGF165mRNA was well related to lymph node metastasisand TNM stages of UICC.The expression levels in patientswith lymph node metastasis and without lymph nodemetastasis were 1.219±0.377 and 0.927±0.205 respectively(P<0.05).The expression in stages Ⅰ,Ⅱ,Ⅲ,Ⅳ was0.934±0.194,1.262±0.386 respectively (P<0.01).Furtheranalysis showed the lymph node metastasis rate in thegroup with over-expression of VEGF was higher than thatin the group with low expression of VEGF (83.3% vs 46.2%),and the ratio of stage Ⅲ+Ⅳ in the group with over-expression of VEGF was also higher than that in the groupwith low expression with VEGF (77.8% vs 33.8%) (P<0.05).The positive rates of expression of VEGF protein and iNOSin 85 cases of gastric cancer were 75.4% and 58.8%respectively,and 50.1% of the patients showed positivestaining both for iNOS and VEGF,the correlation with thetwo factors was significant (P=0.018).But more intensive analysis showed the immunoreactive grades of VEGF werenot associated with that of iNOS.CONCLUSIONS:The expression of VEGF165mRNA is wellrelated with lymph node metastasis and TNM stages of UlCCin gastric cancer,and is concerned with the invasivenessand metastasis of gastric cancer.The relationship can beobserved between the expression of VEGF and iNOS in gastriccancer.