Cyclooxygenase-2 overexpression correlates with vascular endothelial growth factor expression and tumor angiogenesis in gastric cancer

Angiogenesis is a key prerequisite for the successful establishment, growth, and dissemination of tumors. Vascular endothelial growth factor (VEGF) has a potent angiogenic activity and cyclooxygenase-2 (COX-2) promotes angiogenesis by modulated production of angiogenic factors including VEGF. The current study was designed to investigate the possible roles of COX-2 and VEGF in gastric cancer angiogenesis. In this study, we conducted an immunohistochemical investigation of COX-2 and VEGF expression in 97 patients with gastric cancer. To assess tumor angiogenesis, microvessel density (MVD) was determined by CD34 immunohistochemical staining. Expression of COX-2 and VEGF in gastric cancer tissues, was demonstrated in 63.9% and 75.3% of cases, respectively. The expression of COX-2 correlated significantly with VEGF expression. High MVD was significantly associated with depth of tumor invasion and poor survival. The mean MVD value of VEGF positive tumors was 79.8 +/- 32.0 and significantly higher than that of VEGF negative tumors. The mean MVD value of COX-2 positive tumors was 77.9 +/- 29.9 and not significantly higher than that of COX-2 negative tumor. The mean value of MVD in tumors positive for both COX-2 and VEGF was significantly higher than that in tumors negative for both. However, there was no correlation between COX-2 or VEGF expression and various clinicopathological features including patient survival. These results suggest that COX-2 may play an important role in carcinogenesis by stimulating tumor angiogenesis in concert with VEGF in human gastric cancer.     

Inactivation of PTEN is associated with increased angiogenesis and VEGF overexpression in gastric cancer

AIM: To investigate the expression of PTEN/MMAC1/TEP1 and vascular endothelial growth factor (VEGF), their roles in biologic behavior and angiogenesis and their association in gastric cancer.METHODS: Immunohistochemical staining was used to evaluate the expression of PTEN, VEGF and microvascular density (MVD) on paraffin-embedded sections in 70 patients with primary gastric cancer and 24 patients with chronic superficial gastritis (CSG). Expression of PTEN, VEGF and MVD were compared with clinicopathological features of gastric cancer. The relationship between expression of PTEN, VEGF and MVD as well as the relationship between PTEN and VEGF expression in caner cells were investigated. RESULTS: PTEN expression significantly decreased (t= 3.98, P<0.01) whereas both VEGF expression and MVD significant increased (t = 4.29 and 4.41, respectively, both P<0.01) in gastric cancer group compared with CSG group. PTEN expression was significantly down-regulated (t=1.95, P<0.05) whereas VEGF expression (t = 2.37, P<0.05) and MVD (t= 3.28, P<0.01) was significantly up-regulated in advanced gastric cancer compared with early-stage gastric cancer. PTEN expression in gastric cancer showed a negative association with lymph node metastasis (t= 3.91, P<0.01), invasion depth (t= 1.95, P<0.05) and age (t= 4.69, P<0.01). MVD in PTEN-negative gastric cancer was significantly higher than that in PTEN-positive gastric cancer (t=3.69, P<0.01), and there was a negative correlation betweenPTEN expression and MVD (γ=-0.363, P<0.05). VEGF expression was positively associated with invasion depth (especially with serosa invasion, t = 4.69, P<0.01), lymph node metastasis (t= 2.31, P<0.05) and TNM stage (t= 3.04, P<0.01). MVD in VEGF-positive gaslyic cancer was significantly higher than that in VEGF-negative gastric cancer (t=4.62, P<0.01), and there was a positive correlation between VEGF expression of and MVD (y = 0.512, P<0.05). VEGF expression in PTEN-negative gaslyic cancer was significantly stronger than that in PTEN-positive gastric cancer (t=2.61, P<0.05), and there was a significantly negative correlation between the expression of VEGF and PTEN (γ=-0.403, P<0.05).CONCLUSION: Our results imply that inactivation of PTEN gene and over-expression of VEGF contribute to the neovascularization and progression of gastric cancer. PTEN-related angiogenesis might be attributed to its up-regulation of VEGF expression. PTEN and VEGF could be used as the markers reflecting the biologic behaviors of tumor and viable targets in therapeutic approaches to inhibit angiogenesis of gastric cancers.     

Tnactivation of PTEN is associated with increased angiogenesis and VEGF overexpression in gastric cancer

AIM: To investigate the expression of PTEN/MMAC1/TEP1and vascular endothelial growth factor (VEGF), their roles in biologic behavior and angiogenesis and their association in gastric cancer.METHODS: Immunohistochemical staining was used to evaluate the expression of PTEN, VEGF and microvascular density (MVD) on paraffin-embedded sections in 70 patients with primary gastric cancer and 24 patients with chronic superficial gastritis (CSG). Expression of PTEN, VEGF and MVD were compared with clinicopathological features of gastric cancer. The relationship between expression of PTEN, VEGF and MVD as well as the relationship between PTEN and VEGF expression in caner cells were investigated.RESULTS: PTEN expression significantly decreased (t= 3.98,P＜0.01) whereas both VEGF expression and MVD significant increased (t = 4.29 and 4.41, respectively, both P＜0.01)in gastric cancer group compared with CSG group. PTEN expression was significantly down-regulated (t = 1.95,P＜0.05) whereas VEGF expression (t = 2.37, P＜0.05) and MVD (t = 3.28, P＜0.01) was significantly up-regulated in advanced gastric cancer compared with early-stage gastric cancer. PTEN expression in gastric cancer showed a negative association with lymph node metastasis (t= 3.91, P＜0.01),invasion depth (t= 1.95, P＜0.05) and age (t= 4.69, P＜0.01).MVD in PTEN-negative gastric cancer was significantly higher than that in PTEN-positive gastric cancer (t = 3.69,P＜0.01), and there was a negative correlation between PTEN expression and MVD (γ = -0.363, P＜0.05). VEGF expression was positively associated with invasion depth (especially with serosa invasion, t = 4.69, P＜0.01), lymph node metastasis (t= 2.31, P＜0.05) and TNM stage (t= 3.04,P＜0.01). MVD in VEGF-positive gastric cancer was significantly higher than that in VEGF-negative gastric cancer (t = 4.62,P＜0.01), and there was a positive correlation between VEGF expression of and MVD (γ = 0.512, P＜0.05). VEGF expression in PTEN-negative gastric cancer was significantly stronger than that in PTEN-positive gastric cancer (t = 2.61,P＜0.05), and there was a significantly negative correlation between the expression of VEGF and PTEN (γ = -0.403,P＜0.05).CONCLUSION: Our results imply that inactivation of PTEN gene and over-expression of VEGF contribute to the neovascularization and progression of gastric cancer. PTENrelated angiogenesis might be attributed to its up-regulation of VEGF expression. PTEN and VEGF could be used as the markers reflecting the biologic behaviors of tumor and viable targets in therapeutic approaches to inhibit angiogenesis of gastric cancers.     

Microvessel density is a prognostic marker of human gastric cancer

INTRODUCTIONGastric cancer is one of the most frequent and lethal malignancies worldwide, especially in Eastern Asia including China, and the 5-year survival rate is only about 20%[1]. A recent research has shown an increasing trend of gastric cancer mortality in China in the past 20 years, especially in rural areas and among aged people[2]. To date, the treatment outcome of this common malignancy is still not satisfactory. One major difficulty in the diagnosis and treatment of gastric c…     

Expression of survivin in gastric cancer and its relationship with tumor angiogenesis

BACKGROUND/AIMS: Survivin, a member of inhibitors of apoptosis, has been found in various human cancers. Its expression is associated with tumor progression and adverse outcome. Angiogenesis is an essential process for the primary tumor to grow and invade the adjacent normal structures. Angiogenic factors such as vascular endothelial growth factor induce survivin expression in endothelial cells. The current study was designed to investigate the possible role of survivin and vascular endothelial growth factor status for angiogenesis in human gastric cancer. METHODS: In this study, we conducted an immunohistochemical investigation of survivin and vascular endothelial growth factor expression in 106 tissue samples obtained from gastric cancer patients undergoing surgical treatment. To assess tumor angiogenesis, microvessel density was counted by staining endothelial cells immunohistochemically using anti-CD34 monoclonal antibody. RESULTS: The positive expression of survivin and vascular endothelial growth factor in gastric cancer tissues was demonstrated in 50.0 and 69.8% of cases, respectively. The expression of survivin did not associate with vascular endothelial growth factor expression. Expression of survivin was significantly associated with tumor size, depth of invasion, lymph node metastasis, tumor stage and poor survival (P=0.011, 0.004, 0.020, 0.002, 0.046, respectively). High microvessel density was significantly associated with lymph node metastasis and poor survival (P=0.006 and 0.017, respectively). The mean microvessel density value of survivin positive tumors was 87.4+/-34.4 and significantly higher than that of survivin negative tumors (P=0.016). The mean microvessel density value of vascular endothelial growth factor positive tumors was 98.7+/-37.0 and significantly higher than that of vascular endothelial growth factor negative tumors (P=0.001). A combined analysis of survivin and vascular endothelial growth factor status showed that the mean microvessel density value of both positive tumors was 103.7+/-33.1 and significantly higher than that of both negative tumors (P<0.001). CONCLUSION: These results suggest that survivin may play an important role in carcinogenesis by stimulating tumor angiogenesis in human gastric cancer.     

Cyclooxygenase－2 expression and angiogenesis in colorectal cancer

AIM: Cyclooxygenase-2 is involved in a variety of important cellular functions, including cell growth and differentiation,cancer cell motility and invasion, angiogenesis and immune function. However, the role of cyclooxygenase-2 as an angiogenic factor in colorectal cancer tissue is still unclear.We investigated the relationship between cyclooxygenase2 and angiogenesis by analyzing the expression of cyclooxygenase-2 in colorectal cancer tissue, as well as its association with vascular endothelial growth factor (VEGF)and microvascular density (MVD). METHODS: The expression of cydooxygenase-2, VEGF, as well as MVD was detected in 128 cases of colorectal cancer by immunohistochemical staining. The relationship between the cydooxygenase-2 and VEGF expression and MlVD was evaluated.Our objective was to determine the effect of cyclooxygenase2 on the angiogenesis of colorectal cancer tissue. RESULTS: Among 128 cases of colorectal cancer, 87 were positive for cyclooxygenase-2 (67.9 %), and 49 for VEGF (38.3 %), respectively. The microvessel counts ranged from 23 to 142, with a mean of 51.7 (standard deviation, 19.8). The expression of cydooxygenase-2 was correlated significantly with the depth of invasion, stage of disease, metastasis (lymph node and liver), VEGF expression and MlVD. Patients in T3-T4, stage Ⅲ-ⅣV and with metastasis had much higher expression of cydooxygenase-2 than patients in T1-T2, stage Ⅰ-Ⅱ and without metastasis (P＜0.05). The positive expression rate of VEGF (81.6 %) in the cyclooxygenase-2 positive group was higher than that in the cyclooxygenase-2 negative group (18.4 %,P＜0.05). Also, the microvessel count (56±16) in cyclooxygenase-2 positive group was significantly higher than that in cyclooxygenase-2 negative group (43±12, P＜0.05). The microvessel count in tumors with positive cyclooxygenase-2and VEGF was the highest (60±18, 41-142, P＜0.05), whereas that in tumors with negative cyclooxygenase-2 and VEGF wasthe lowest (39±16, 23-68, P＜0.05). CONCLUSION: Cyclooxygenase-2 may be associated with tumor progression by madulating the angiogenesis in colorectal cancer tissue and used as a possible biomarker.     

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

AIM：To in vestigate the relationship between the expression of inducible nitric oxide synthase(iNOS),vascular endothelial growth factor(VEGF),the microvascular density(MVD)and the pathological features and clinical staging of gastric cancer.METHODS:Immunohistochemical staining was used for detecting the expression of iNOS and VEGFin46resected specimens of gastric carcinoma;the monoclonal antibody against CD34 was used for displaying vascular endothelial cells,and MVD was detected by counting of CD34-positive vascular endothelial cells.RESULTS:Of 46resected specimens of gastric carcinoma,the rates of expressions of iNOS and VEGF were 58.70%and76.09%,respectively,and MVDaveraged55.59&#177;19.39,Judged by the standard TNM criteria,the rate of expression of iNOS in stageⅣ（84.46%)was higher than those in stageⅠ,Ⅱ,Ⅲ（Fish exact probabilities test,P=0.019,0.023and 0.033,respectively);the rates of expression of VEGFin stage Ⅲ,Ⅳ（76.0%,92.31%,respectively)were higher than those in stageⅠ,Ⅱ（Fis exact probabilities test,P=0.031,0.017,0.022and0.019).MVDs in stageⅢ,Ⅳ（64.72&#177;14.96,67.09&#177;18.29,respectively)were higher than those in stageⅠ,Ⅱ(t\2.378,4.015,2.503and2.450,P&lt;0.05,P&lt;0.001,P&lt;0.001,P&lt;0.05,respectively),In37gastric carcinoma specimens with lymph node metastasis,MVD(68.69&#177;18.07)and the rates of expression of iNOS and VEGF(70.27%,83.78%,respectively)were higher than those in the specimens with absence of metastasis(t=2.205,X^2=6.3587,X^2=6.2584,P&lt;0.01,P&lt;0.05,P&lt;0.05,respectively),MVD and the expressions of iNOS and EGF were not correlated to the location,size or grade of tumor,nor with the depth of invasion of tumor;MVDs in the positive iNOS and VEGF specimens(59.88&#177;18.02,58.39&#177;17.73,repectively)were higher than those in the negative iNOS and VEGF specimens(X^2=6.3587and 6.1574,P&lt;0.05,P&lt;0.05,respectively);thus the expressions of iNOS and VEGF was correlated to MVD,but the expression of iNOS was not correlated to that of VEGF,In addition.of the 46 surviving patients,the 5-year survival rate of patients with positive iNOS or VEGF tumors was significantly less than that of patients with negative iNOS-or VEGF tumors(X^2=4.3842and 5.4073,P&lt;0.05,P&lt;0.05.respectively).CONCLUSION:The expressions of iNOS and VEGF are colosely related to tumor angiogenesis,and are involved in the advancement and the lymph node metastasis;thusMVD and the expressions of iNOS and EGF may serve indexes for evaluating staging of gastric carcinoma and forecasting its risk of metastasis,which will help establish a comprehensive therapeutical measure of post-operative patients and provide a new approach to tumor therapy.     

Relationship between expression of CD105 and growth factors in malignant tumors of gastrointestinal tract and its significance

AIM: Angiogenesis is an important step in the growth of solid malignant tumors. A number of angiogenic factors have been found such as transforming growth factorβ1 (TGF-β1)and vascular endothelial growth factor (VEGF). However,the roles of TGFβ1 and VEGF in gastrointestinal carcinogenesis are still unclear. This study was to investigate the expressions of TGF-β1 and VEGF in gastrointestinal tract malignant tumors, as well as their association with microvessel density (MVD). At the same time, we also observed the localization of TGF-β1 and its receptor CD105 in gastric malignant tumors.METHODS: The expressions of TGF-β1 and CDL05 were detected in 55 fresh specimens of gastric carcinoma and VEGF and CD105 in 44 fresh specimens of colorectal carcinoma by immunohistochemical staining (S-ABC). TGF-β1 and CD105 in 55 gastric carcinoma tissues on the same slide were detected by using double-stain Tmmunohistochemistry (DS-ABC).RESULTS: Among the 55 cases of gastric carcinoma tissues,30 were positive for TGF-β1 (54.55 %). The MVD of TGF-β1 strong positive group (++～+++ 23.22±5.8) was significantly higher than that of weak positive group (+17.56±7.2) and negative group (- 17.46±3.9) (q=4.5, q=5.3207, respectively,P＜0.01). In the areas of high expression of TGF-β1, MVD and the expression of CD105 were also high. Among the 44 cases of colonic carcinoma tissues, 26 were positive for VEGF (59.1%). The expressions of both VEGF and CD105 (MVD)were related with the depth of invasion (F=5.438, P＜0.05;F=4.168, P=0.05), lymph node metastasis (F=10.311, P＜0.01;F=20.282, P＜0.01) and Dukes stage (F=6.196, P＜0.01;F=10.274, P＜0.01), but not with histological grade (F=0.487,P＞0.05). There was a significant correlation between the expression of VEGF and CD105 (MVD) (r=0.720, P＜0.01).CONCLUSION: Over-expression of TGF-β1 and VEGF acts as stimulating factors of angiogenesis in gastrointestinal tumors.CD105, as a receptor of TGF-β1, can regulate the biological effect of TGF-β1 in tumor angiogenesis. MVD marked by CD105 is more suitable for detecting newborn blood vessels.     

Expression of tissue factor and vascular endothelial growth factor is associated with angiogenesis in colorectal cancer

We examined the expression of tissue factor (TF) and vascular endothelial growth factor (VEGF) and the microvessel density (MVD) in 100 patients with colorectal cancer, and we investigated the relationship of the expression of TF or VEGF with angiogenesis. TF antigen was positive in 57.0% of all specimens. Incidence of TF expression was 41.2%, 45.5%, 52.6%, 84.6%, and 81.3% in tumors from patients in clinical stages I, II, IIIA, IIIB, and IV, respectively. TF expression was correlated with the Dukes' classification (P = 0.01) and the clinical stage of colorectal cancer (P = 0.02). VEGF antigen was positive in 64.0% of all specimens. Incidence of VEGF expression was 41.2%, 57.6%, 73.7%, 84.6%, and 75.0% in tumors from patients in clinical stages I, II, IIIA, IIIB, and IV, respectively. VEGF expression was correlated with the Dukes' classification (P = 0.01) but showed a weak association with the clinical stage (P = 0.08). MVD was significantly associated with the depth of invasion (P = 0.01), lymph node metastasis (P = 0.001), and liver metastasis (P = 0.02). The mean values of MVD were 7.5 +/- 2.8, 10.1 +/- 5.7, 14.6 +/- 5.8, 13.5 +/- 3.9, and 15.9 +/- 4.2 in tumors from patients in clinical stages I, II, IIIA, IIIB, and IV, respectively. A close relationship between VEGF and MVD (P < 0.001) and a significant correlation between TF expression and MVD were observed (P = 0.02). TF-positive carcinomas presented high MVD and VEGF expression (P < 0.001) more frequently than did TF-negative tumors. These results suggest that involvement of TF in the process of metastasis and progression of colorectal cancer may depend on increased angiogenesis.     

TGF beta1 expression and angiogenesis in colorectal cancer tissue

AIM: Transforming growth factor TGF beta1 is involved in a variety of important cellular functions,including cell growth and differentiation, angiogenesis, immune function and extracellular matrix formation. However, the role of TGF beta(1) as an angiogenic factor in colorectal cancer is still unclear. We investigate the relationship between transforming growth factor beta(1) and angiogenesis by analyzing the expression of transforming growth factor TGF beta(1) in colorectal cancer, as well as its association with VEGF and MVD. METHODS: The expression of TGF beta(1),VEGF, as well as MVD were detected in 98 colorectal cancer by immunohistochemical staining. The relationship between the TGF beta(1) expression and VEGF expression,MVD was evaluated. To evaluate the effect of TGF beta(1) on the angiogenesis of colorectal cancers. RESULTS: Among 98 cases of colorectal cancer,37 were positive for TGF beta(1) 37.8% 36 for VEGF 36.7% respectively. The microvessel counts ranged from 19 to 139.8, with a mean of 48.7(standard deviation,21.8).The expression of TGF beta(1) was correlated significantly with the depth of invasion, stage of disease, lymph node metastasis, VEGF expression and MVD. Patients in T3-T4, stage III-IV and with lymph node metastasis had much higher expression of TGF beta(1) than patients in T1-T2, stage I-II and without lymph node metastasis (P<0.05). The positive expression rate of VEGF(58.3%) in the TGF-beta(1) positive group is higher than that in the TGF-beta(1) negative group(41.7%, P<0.05). Also, the microvessel count (54+/-18) in TGF-beta(1) positive group is significantly higher than that in TGF-beta(1) negative group(46+/-15, P<0.05). The microvessel count in tumors with both TGF-beta(1) and VEGF positive were the highest (58+/-20 36-140, P<0.05).Whereas that in tumors with both TGF-beta(1) and VEGF negative were the lowest (38+/-16, 19-60, P<0.05). CONCLUSION: TGF beta(1) might be associated with tumor progression by modulating the angiogenesis in colorectal cancer and TGF beta(1) may be used as a possible biomarker.     

Prognostic significance of vascular endothelial growth factor expression and microvessel density in carcinoma of ampulla of Vater

BACKGROUND/AIMS: To investigate whether the expression of vascular endothelial growth factor (VEGF) and microvessel density (MVD) are of prognostic significance in ampullary carcinoma. METHODOLOGY: Twenty-two resected tumor specimens from patients with ampullary carcinoma were immunohistochemically stained for VEGF and CD34 (surrogate for vessels) by streptavidin-peroxidase method. RESULTS: Expression of VEGF in tumor tissue was found in 50% of patients. The mean MVD for entire group was 26.4 +/- 12.8. A significantly higher MVD was observed in the tumors with positive VEGF expression (35.0 +/- 9.6) compared with that of negative VEGF expression (17.7 +/- 9.3) (p<0.01). The expression of VEGF and MVD were closely related lymph node status and tumor TNM stage. The positive expression rate of VEGF and the average MVD in patients with lymph node metastases were 85.7% and 33.1 +/- 10.8 respectively, which were significantly higher than those in patients without lymph node metastases (33.3% and 22.8 +/- 11.8 respectively) (p<0.05). The positive expression rate of VEGF and the average MVD in patients with stage III and were 75% and 36.3 +/- 8.4 respectively, which were significantly higher than those in patients with stage I (25% and 18.4 +/- 10.1 respectively) or stage II (50% and 23.8 +/- 13.4 respectively) (p<0.05). The Kaplan-Meier survival curves showed that the 3-year survival rate for patients with positive VEGF expression or a high MVD (9.1% and 10% respectively) were lower than those in patients with negative VEGF expression or a low MVD (63.64% and 58.33% respectively) (p<0.05). CONCLUSIONS: VEGF is positively correlated with MVD in ampullary carcinoma. VEGF and angiogenesis may play an important role in lymph node metastasis and progression of ampullary carcinoma. VEGF and MVD appear to be important prognostic predictor in patients with ampullary carcinoma.     

血管内皮细胞生长因子的表达及微血管密度与胆囊癌浸润、转移及预后的相关研究

探讨血管内皮细胞生长因子 (vascularendothelialgrowthfactor,VEGF)及微血管密度 (Microvesseldensity ,MVD)在胆囊癌发生发展中的作用及与胆囊癌浸润、转移及预后的关系。应用S -P免疫组化技术对 3 1例经手术切除的原发性胆囊癌及 10例经手术切除的慢性胆囊炎标本进行VEGF蛋白和微血管密度检测。 3 1例胆囊癌组织中癌旁VEGF表达及MVD值均明显高于癌中央及正常组织 ,三者差异具有显著性 (P <0 0 1) ;VEGF表达与MVD具有相关性 ,VEGF阳性者MVD值显著高于阴性者 (P <0 0 1) ;VEGF表达和MVD与胆囊癌分化程度、浸润转移、Nevin分期密切相关 (P <0 0 1) ;VEGF阳性者及高MVD者预后较阴性者差 ;Cox比例危险模型多因素分析表明 :VEGF对胆囊癌是一个独立的预后因子。VEGF的表达及MVD在胆囊癌的发生和浸润转移过程中发挥重要的作用 ,VEGF和MVD可作为反映胆囊癌生物学行为的指标     

Effect of non-anticoagulant N-desulfated heparin on expression of vascular endothelial growth factor, angiogenesis and metastasis of orthotopic implantation of human gastric carcinoma

AIM： To investigate the effect of N-desulfated heparin on tumor metastasis and angiogenesis, and expression of vascular endothelial growth factor （VEGF） of orthotopic implantation of human gastric carcinoma in male severe combined immune deficiency （SCID） mice.
METHODS： Human gastric cancer SGC-7901 cells were orthotopically implanted into the stomach of SC/D mice. The mice were randomly divided into normal saline group and N-desulfated heparin group. One week after operation, the mice in N-desulfated heparin group reo ceived i.v. injections of N-desulfated heparin （Shanghai Institute of Cell Biology, Chinese Academy of Sciences, 10 mg/kg.d） twice weekly for 3 wk. The mice in normal saline group received i.v. injections of normal saline （100 μL） twice weekly for 3 wk. The mice were sacrificed six weeks after implantation. Tumor metastasis was evaluo ated histologically for metastasis under microscope. Intratumoral microvessel density （MVD） and VEGF expression were evaluated immuohistochemically. VEGF mRNA expression in gastric tissue of SC/D mice was detected by real time PCR.
RESULTS： The tumor metastasis rate was 80% in normal saline group and 20% in N-desulfated heparin group （P 〈 0.05）. MVD was 8.0 ± 3.1 in normal saline group and 4.3 ± 1.8 in N-desulfated heparin group （P 〈 0.05）. VEGF positive immunostaining was found in cytoplasm of cancer cells. The rate of VEGF positive expression was higher in normal saline group than in N-desulfated hepa- rin treated group （90% vs 20%, P 〈 0.05）. VEGF mRNA expression was significantly inhibited by N-desulfated heparin and was higher in normal saline group than in N-desulfated heparin group （Ct value 19.51 ± 1.01 vs 22.55± 1.36, P 〈 0.05）. N-desulfated heparin significantly inhibited the expression of VEGF mRNA in cancer cells. No bleeding occurred in N-desulfated heparin group. CONCLUSION： N-desulfated heparin can inhibit metastasis of gastric cancer by suppressing tumor VEGF expression and tumor angiogenesis     

Overexpression of cyclooxygenase-2 and tumor angiogenesis in human gastric cancer

BACKGROUND/AIMS: Cyclooxygenase-2 (COX-2) protein is overexpressed in various cancers, including esophageal, gastric, colon, and pancreatic. To better comprehend the role of COX-2 in gastric cancer, especially with regard to angiogenesis, we investigated COX-2 and vascular endothelial growth factor (VEGF) expression and microvessel density (MVD) in 108 patients with gastric cancer. METHODOLOGY: We used immunohistochemical analysis of formalin-fixed tissues of gastric cancer. RESULTS: Expression of COX-2 showed diffuse staining in the cytoplasm of tumor cells, however, no staining in normal epithelial cells. Of the 108 tumors examined, 71 (65%) were positive for COX-2 expression, the VEGF-positive cases numbered 43 of 108 cases (39.8%). The intensity of COX-2 expression did not correlate with any clinicopathological characteristics. The positive rate of VEGF expression in COX-2-positive cases was significantly higher than in COX-2-negative ones (47.9% vs. 24.3%, P<0.05). MVD in COX-2-positive cases was significantly higher than in COX-2-negative ones (22.0+/-7.8 vs. 18.5+/-7.5/1 mm2; P<0.05). CONCLUSIONS: Our study provides evidence that COX-2 is closely related with angiogenesis.     

Growth,invasion, metastasis,differentiation, angiogenesis and apoptosis of gastric cancer regulated by expression of PTEN encoding products

AIM: To investigate expression of PTEN in gastric cancer and to explore its roles in tumorigenesis and progression of gastric cancer.METHODS: Formalin-fixed and paraffin-embedded tissues of adjacent non-tumor mucosa and primary foci from 113cases of gastric cancers were studied for the expression of PTEN and Caspase-3 andmicrovessel density (MVD)by streptavidin-peroxidase (S-P) immunohistochemistry with antibodies against PTEN, Caspase-3, and CD34. The relationship between PTEN and Caspase 3 expression and clinicopathological parameters of tumors was compared.RESULTS: Primary gastric cancer cells expressed PTEN less frequently than adjacent epithelial cells of primary foci (54.9％ vs89.4％; P=0.000, χ2=33.474). PTEN expression was significantly associated with invasive depth (P=0.003,rs=0.274), metastasis (P=0.036, rs=0.197), growth pattern (P=0.008, rs=0.282), Lauren′s classification (P=0.000,rs=0.345), and histological classification (P=0.005, rs=0.262)of tumors, but not with tumor size (P=0.639, rs=0.045),Borrmann′s classification (P=0.544, rs=0.070) or TNM staging (P=0.172, rs=0.129). PTEN expression was negatively correlated with MDV in primary gastric cancer (P=0.020,F=5.558). Primary gastric cancer cells showed less frequent immunoreactivity to Caspase-3 than adjacent epithelial cells of primary foci (32.7 ％ vs 50.4 ％; P=0.007,χ2=7.286).Caspase-3 expression was dependent of PTEN expression in primary gastric cancer cells (P=0.000, χ2=15.266).CONCLUSION: Down-regulated expression of PTEN plays an important role in tumorigenesis, progression, growth,differentiation and angiogenesis of gastric cancer. Low expression of PTEN can decrease expression of Caspase-3to disorder apoptosis of tumor cells, which might explain the molecular mechanisms of PTEN contributions to tumorigenesis and progression of gastric cancer.