Relationship between the expression of iNOS, VEGF, tumor angiogenesis and gastric cancer

AIM: To investigate the relationship between theexpression of inducible nitric oxide synthase(iNOS),vascular endothelial growth factor(VEGF),themicrovascular density(MVD) and the pathologicalfeatures and clinical staging of gastric cancerMETHODS: Immunohistochemical staining was used fordetecting the expression of iNOS and VEGF in 46resected specimens of gastric carcinoma; themonoclonal antibody against CD34 was used fordisplaying vascular endothelial cells, and MVD wasdetected by counting of CD34-positive vascularendothelial cells.RESULTS: Of 46 resected specimens of gastriccarcinoma,the rates of expressions of iNOS and VEGFwere 58.70% and 76.09%, respectively,and MVDaveraged 55.59± 19.39.Judged by the standard TNMcriteria, the rate of expression of iNOS in stage ⅣV(84.46%) was higher than those in stage Ⅰ, Ⅱ, Ⅲ(Fishexact probabilities test, P=0.019,0.023 and 0.033,respectively);the rates of expression of VEGF in stageⅢ, Ⅳ (76.0%,92.31%, respectively) were higher thanthose in stage Ⅰ, Ⅱ (Fish exact probabilities test,P=0.031,0.017,0.022 and 0.019). MVDs in stage Ⅲ, Ⅳ(64.72 ± 14.96,67.09± 18.29,respectively) werehigher than those in stage Ⅰ ,Ⅱ(t=2.378,4.015,2.503and 2.450,P＜0.05,P＜0.001,P＜0.001,P＜0.05,respectively). In 37 gastric carcinoma specimens withlymph node metastasis, MVD(68.69±18.07) and therates of expression of iNOS and VEGF(70.27%,83.78%,respectively) were higher than those in the specimenswith absence of metastasis (t=2.205, x2=6.3587,x2=6.2584,P＜0.01, P＜0.05,P＜0.05, respectively). MVDand the expressions of iNOS and VEGF were notcorrelated to the location ,size or grade of tumor, nor withthe depth of invasion of tumor; MVDs in the positive iNOSand VEGF specimens(59.88±18.02,58.39±17.73,respectively) were higher than those in the negative iNOSand VEGF specimens (x2=6.3587 and 6.1574, P＜0.05,P＜0.05,respectively) ;thus the expressions of iNOS andVEGF was correlated to MVD, but the expression of iNOSwas not correlated to that of VEGF. In addition,of the46 surviving patients, the 5-year survival rate ofpatients with positive iNOS or VEGF tumors wassignificantly less than that of patients with negativeiNOS-or VEGF tumors(x2=4.3842 and 5.4073,P＜0.05,P＜ 0.05,respectively).CONCLUSION: The expressions of iNOS and VEGF areclosely related to tumor angiogenesis, and are involvedin the advancement and the lymph node metastasis;thus MVD and the expressions of iNOS and VEGF mayserve indexes for evaluating staging of gastriccarcinoma and forecasting its risk of metastasis, whichwill help establish a comprehensive therapeuticalmeasure of post-operative patients and provide a newapproach to tumor therapy.