Expression of E26 transformation-specific-1, matrix metalloproteinases-1 and vascular endothelial growth factor in colorectal carcinoma

AIM: To study the expression of E26 transformation-specific-1 (Ets-1), matrix metalloproteinases-1 (MMP-1) and vascular endothelial growth factor (VEGF) in human colorectal carcinoma, and to explore the role of Ets-1 in the angiogenesis and metastasis of carcinoma.

METHODS: The expression of Ets-1, MMP-1 and VEGF were detected in colorectal carcinoma (n = 61) and normal colon tissues (n = 21) by the immunohistochemical method respectively.

RESULTS: Ets-1, MMP-1 and VEGF were negatively expressed in all normal mucosal tissues. The positive rates of Ets-1, MMP-1 and VEGF expression were 75.4%, 78.7% and 82.0% in colorectal carcinoma respectively. No significant correlation was found between their positive rates and tumor′s size as well as the differentiation (P >0.05). The expression of Ets-1, MMP-1 and VEGF were significantly correlated with Duke's staging (χ² = 10.718, P <0.01; χ² = 8.323, P <0.01; χ² = 6.145, P <0.05), the depth of invasion (χ² = 7.705, P <0.01; χ² = 19.101, P <0.01; χ² = 14.707, P <0.01), lymphatic invasion (χ² = 9.333, P <0.01; χ² = 3.965, P <0.05; χ² = 4.638, P <0.05) and distant metastasis (χ² = 5.472, P <0.05; χ² = 4.125, P <0.05; χ² = 5.034, P <0.05). Ets-1 expression was positively associated with MMP-1 and VEGF level (r = 0.447, P <0.01; r = 0.425, P <0.05).

CONCLUSION: Ets-1 was over-expressed in colorectal carcinoma, and its expression was related to clinical staging, invasion and metastasis. Ets-1 expression was also positively related to MMP-1 and VEGF level. Their expression can become referential indexes to predict the malignant behavior of colorectal carcinoma.

Clinical significance of detection for vascular endothelial growth factor in resection margin following total mesorectal excision

AIM: To investigate the expression and its significance of vascular endothelial growth factor (VEGF) in the resection margin following total mesorectal excision (TME) for human rectal cancer.

METHODS: VEGF was detected in the tissue specimens of cancer, distal mesorectal margin (DMM), circumferential resection margin (CRM) and outer pelvic fascia from 60 rectal cancer patients received TME. The pathological data were retrospectively analyzed.

RESULTS: VEGF expression was significantly higher in the tissues of rectal cancer than that in the normal tissues (54/60 vs2/20, P < 0.001). VEGF was also expressed in tissues of CRM (9/60). However, no VEGF expression was detected in the tissues of DMM and outer pelvic fascia. VEGF expression was closely related with the differentiation degree, Dukes staging and lymph node metastasis (P < 0.05 or P < 0.01).

CONCLUSION: VEGF is highly expressed in tissues of rectal cancer, and negatively or weakly positively expressed in DMM and CRM.

Effect of c-fos antisense probe on prostaglandin E2 -induced upregulation of vascular endothelial growth factor mRNA in human liver cancer cells

AIM: To examine the effect of prostaglandin E₂ (PGE₂) on the expression of vascular endothelial growth factor (VEGF) mRNA in the human hepatocellular carcinoma (HCC) HepG2 cells and the possible involvement of c-fos protein in this process.

METHODS: Human HCC HepG2 cells were divided into three groups treated respectively with PGE₂, a combination of PGE₂ and c-fos antisense oligodeoxynucleotide (ASO), and PGE₂ plus c-fos sense oligodeoxynucleotide (SO). The expression of VEGF mRNA in HepG2 cells after different treatments was detected by reverse transcriptase-polymerase chain reaction (RT-PCR). The relative expression level of VEGF mRNA in HepG2 cells in each group was measured.

RESULTS: Administration of PGE₂ resulted in an increased expression of c-fos and VEGF mRNA in HepG2 cells. The relative expression level of c-fos mRNA reached the peak at 3 h (68.44.7%) after PGE₂ treatment, which was significantly higher than that at 0 h (20.6±1.7%, P<0.01). Whereas, the highest expression level of VEGF mRNA was observed at 6 h (100.5±6.1%) after PGE₂treatment, which was significantly higher than that at 0 h (33.2±2.4%, P<0.01). C-fos ASO significantly reduced PGE₂-induced VEGF mRNA expression in HepG2 cells.

CONCLUSION: PGE₂ increases the expression and secretion of VEGF in HCC cells by activating the transcription factor c-fos, promotes the angiogenesis of HCC and plays an important role in the pathogenesis of liver cancer.

Treatment of metastatic colorectal carcinomas by systemic inhibition of vascular endothelial growth factor signaling in mice

AIM: Tumor angiogenesis has been shown to be promoted by vascular endothelial growth factor (VEGF) via stimulating endothelial cell proliferation, migration, and survival. Blockade of VEGF signaling by different means has been demonstrated to result in reduced tumor growth and suppression of tumor angiogenesis in distinct tumor entities. Here, we tested a recombinant adenovirus, AdsFlt1-3, that encodes an antagonistically acting fragment of the VEGF receptor 1 (Flt-1), for systemic antitumor effects in pre-established subcutaneous CRC tumors in mice.

METHODS: Murine colorectal carcinoma cells (CT26) were inoculated subcutaneously into Balb/c mice for in vivo studies. Tumor size and survival were determined. 293 cell line was used for propagation of the adenoviral vectors. Human lung cancer line A₅₄₉ and human umbilical vein endothelial cells were transfected for in vitro experiments.

RESULTS: Infection of tumor cells with AdsFlt1-3 resulted in protein secretion into cell supernatant, demonstrating correct vector function. As expected, the secreted sFlt1-3 protein had no direct effect on CT26 tumor cell proliferation in vitro, but endothelial cell function was inhibited by about 46% as compared to the AdLacZ control in a tube formation assay. When AdsFlt1-3 (5×10⁹ PFU/animal) was applied to tumor bearing mice, we found a tumor inhibition by 72% at d 12 after treatment initiation. In spite of these antitumoral effects, the survival time was not improved. According to reduced intratumoral microvessel density in AdsFlt1-3-treated mice, the antitumor mechanism can be attributed to angiostatic vector effects. We did not detect increased systemic VEGF levels after AdsFlt1-3 treatment and liver toxicity was low as judged by serum alanine aminotransferase determination.

CONCLUSION: In this study we confirmed the value of a systemic administration of AdsFlt1-3 to block VEGF signaling as antitumor therapy in an experimental metastatic colorectal carcinoma model in mice.

Anti-cancer effect of iNOS inhibitor and its correlation with angiogenesis in gastric cancer

AIM: To observe the anti-cancer effect of iNOS selective inhibitor (aminoguanidine, AG) and investigate the relationship between iNOS inhibitor and angiogenesis, infiltration or metastasis in MFC gastric cancer xenografts.

METHODS: Fifty athymic mice xenograft models were established by inoculating gastric cancer cell MFC subcutaneously. Twenty-four hours later, 0.9% sodium chloride solution, mitomycin, low dosage AG, high dosage AG, mitomycin and AG were administered by intraperitoneal injection respectively. Thus these mice were divided into five groups of 10 each randomly: control group, MMC group, AG_L group, AG_H group, MMC+AG_H group. Two weeks later the mice were killed, and the tumor weight, inhibitory rate were evaluated. Greiss assay was used to detect the nitric oxide levels in plasma. HE and immunohistochemistry staining were used to examine microvessel density (MVD) and the expression of iNOS, VEGF, and PCNA. Apoptosis was detected by using TUNEL assay.

RESULTS: The inhibitory rates in MMC+AG_H group and AG_H group were 52.9% and 47.1% respectively, which is significant statistically compared with that of control group (0). In treatment groups, the cell proliferation index (PI) was lower and apoptosis index was higher than those of control group. Microvessel density, iNOS, and VEGF in MMC+ AG_H group were 8.8 ± 2.6, 2.4 ± 1.1, and 2.1 ± 1.4 respectively, which is significant statistically compared with those of control group (68.3 ± 10.6, 11.3 ± 1.3, and 10.3 ± 1.6). The NO level in plasma of MMC+ AG_H and AG_H group were 12.7 ± 2.1 and 12.9 ± 2.0 μmol/L. Compared with that of control group (46.6 ± 2.3 μmol/L), the difference is statistically significant.

CONCLUSION: AG has anticancer effect on gastric cancer, and it has positive synergistic effect with chemotherapeutic drugs. It may play important inhibitory roles in angiogenesis of gastric cancer. The anticancer effect of iNOS inhibitors may include inducing cell apoptosis, suppressing cell proliferation and reducing angiogenesis.

Expression and significance of new inhibitor of apoptosis protein survivin in hepatocellular carcinoma

AIM: To investigate expression and significance of inhibitor of apoptosis protein survivin in hepatocellular carcinoma (HCC).

METHODS: The expression of survivin and vascular endothelial growth factor (VEGF) was investigated in 38 cases of HCC tissues and 38 liver cirrhosis tissues by immunohistochemistry and Western blot. The relationship between the expression of survivin and clinicopathological factors of HCC was analyzed.

RESULTS: Survivin protein was detected in 23 (60.5%) of 38 HCCs and 3 (7.9%) of 38 liver cirrhosis tissues. In 23 cases of HCC which expressed survivin, the expression of VEGF was positive in 18 cases and slight positive or negative in 5 cases. While in 15 cases of HCC which did not express survivin, 12 cases did not express or slightly expressed, and 3 cases expressed VEGF. In liver cirrhosis tissues, the expression of VEGF was as follows: 24 cases were negative, 10 cases were weak positive and 4 cases were strong positive. The expression of survivin was coincident with the expression of VEGF in HCC (P < 0.01). The expression of survivin in HCC had no relationship with the patients’ age, gender, tumor size and differentiation level of HCC, while it was related to the metastasis of HCC. The protein quantitative analysis by Western blot also showed that overexpression of survivin in HCC was closely correlated to the expression of VEGF (P < 0.01). Furthermore, stronger expression of survivin and VEGF was also found in patients with metastasis rather than in those with no metastasis (P < 0.01).

CONCLUSION: Survivin plays a pivotal role in the metastasis of HCC, and it has some correlation with tumorigenesis. The expression of survivin in the primary lesion is very useful as an indicator for metastasis and prognosis of HCC. It could become a new target of gene therapy of HCC.

Cyclooxygenase-2 promotes angiogenesis by increasing vascular endothelial growth factor and predicts prognosis in gallbladder carcinoma

AIM: To investigate the relationships between the expression of cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF) and the degree of vascularization, clinicopathologic feature, survival time of patients with gallbladder carcinomas.

METHODS: Sixty-four gallbladder carcinoma specimens were evaluated for COX-2, VEGF expression by immunohi-stochemical methods. Microvessel counts (MVC) were determined using CD₃₄. The relationships between COX-2, VEGF expression, CD₃₄-stained MVC, clinicopathologic features and survival time were analyzed. The correlations between COX-2 and VEGF expression, CD₃₄-stained MVC were also investigated.

RESULTS: COX-2, VEGF immunoreactivity were observed in 71.9% (46/64) and 54.7% (35/64) specimens, respectively. The average MVC in 64 cases of gallbladder carcinoma was 57±14 per high power vision field. The status of MVC was closely correlated with Nevin staging, tumor differentiation and lymph node metastasis (P<0.01, 0.002, and 0.003, 0.000, respectively). Increased VEGF expression was significantly correlated with tumor differentiation (poorly and moderately>well differentiated, P<0.05, P = 0.016). Clinical stages had no relation with the expression of VEGF (P>0.05, P = 0.612). There was a positive correlation between COX-2 expression and clinical stages. The positive rate of COX-2 was higher in cases of Nevin stages S₄-S₅ (81.8%) than in those of Nevin stages S₁-S₃ (50.0%) with a statistical significance (P<0.01, P = 0.009). The expression of COX-2 did not vary with differentiation (P>0.05, P = 0.067). Statistically significant differences were also observed according to lymph node metastasis, COX-2 expression and VEGF expression (P<0.01, 0.000, and 0.001, respectively). There was no relation between VEGF, COX-2 expression, MVC and the age and sex of patients. MVC and VEGF positive rate in the COX-2 positive gallbladder carcinoma tissue was higher than that in the COX-2 negative tissue (P<0.05, 0.000, and 0.032, respectively). Patients with VEGF, COX-2 positive tumors had a significantly shorter survival time than those with negative tumors (P<0.05, 0.004, 0.01, respectively).

CONCLUSION: Augmented tumor neovascularization induced by VEGF may be one of the several effects of COX-2 responsible for poor prognosis of human gallbladder carcinoma. COX-2 inhibitor, either in combination therapy with other agents, or for chemoprevention, may be effective via suppression of angiogenesis in this fatal disease.

Effect of VEGF expression up-regulated by nuclear factor-κB prognosis of gastric carcinoma

AIM: To investigate the up-regulation of vascular endothelial growth factor (VEGF) induced by the activation of nuclear factor-κB (NF-κB) and its effect on the prognosis of gastric carcinoma.

METHODS: Forty-one gastric carcinoma specimens were obtained by surgery and the expression of NF-κB, VEGF and CD34 were detected in paraffin-embedded tissue sections by immunohistochemical method.

RESULTS: NF-κB was activated and expressed in 68.3% (28/41) gastric carcinoma and VEGF was expressed in 70.7% (29/41). A significant correlation was found between NF-κB activation and VEGF expression(k = 0.393, P = 0.012). The microvessel Density in co-expression of NF-κB and VEGF group was significantly higher than that in non-expression group (P = 0.000). The co-expression of NF-κB and VEGF group showed markedly poorer prognosis than that did in non-expression group (P = 0.035).

CONCLUSION: The activation of NF-κB contributes to tumor angiogenesis in gastric carcinoma by up-regulation of VEGF, which results in a poorer prognosis.

Tumor cyclooxygenase-2 levels correlate with tumor invasiveness in human hepatocellular carcinoma

AIM: Recent studies suggested that cyclooxygenase-2 (COX-2) enhances tumor angiogenesis via upregulation of vascular endothelial growth factor (VEGF). Although COX-2 expression has been demonstrated in hepatocellular carcinoma (HCC), the significance of COX-2 in progression of HCC remains unclear. This study evaluated the clinico-pathological correlation of COX-2 level and its relationship with VEGF level in HCC.

METHODS: Fresh tumor tissues were obtained from 100 patients who underwent resection of HCC. COX-2 protein expression was examined by immunohistochemistry, and quantitatively by an enzyme immunometric assay (EIA) of tumor cytosolic COX-2 levels. Tumor cytosolic VEGF levels were measured by an ELISA.

RESULTS: Immunostaining showed expression of COX-2 in tumor cells. Tumor cytosolic COX-2 levels correlated with VEGF levels (r = 0.469, P<0.001). Correlation with clinicopathological features showed significantly higher tumor cytosolic COX-2 levels in the presence of multiple tumors (P = 0.027), venous invasion (P = 0.030), microsatellite lesions (P = 0.037) and advanced tumor stage (P = 0.008). Higher tumor cytosolic COX-2 levels were associated with worse patient survival.

CONCLUSION: This study shows that elevated tumor COX-2 levels correlate with elevated VEGF levels and invasiveness in HCC, suggesting that COX-2 plays a significant role in the progression of HCC.

Expression of hypoxia-inducible factor 1α and vascular endothelial growth factor in hepatocellular carcinoma: Impact on neovascularization and survival

AIM: To study the expression of hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) in hepatocellular carcinoma (HCC) and the impact on neovascularization and survival.

METHODS: Expressions of HIF-1α, VEGF and microvessel density (MVD) are studied through immunohistochemistry in 36 cases of HCC and the corresponding paraneoplastic tissue and 6 cases of normal liver tissue. The relationship of the expressions of HIF-1α and VEGF with the clinicopathological data and survival are analyzed.

RESULTS: The positive rate of VEGF in HCC was 32/36, which is significantly higher than that in paraneoplastic tissue and normal liver tissue (P<0.05). The expression of HIF-1α in HCC tissue is 24/36, also higher than that in paraneoplastic tissue and normal liver tissue (P<0.05). The expression of VEGF and HIF-1α in HCC with microscopic venous invasion is significantly higher than that in HCC without microscopic venous invasion (P<0.05). Spearman correlation analysis does not only show the expression of HIF-1α as correlated with the expression of VEGF (rs = 0.459, P<0.01), but it also shows the expression of HIF-1α and VEGF as correlated with MVD (rs = 0.412 and 0.336, respectively, P<0.05). The differences of the survival rates among VEGF positive group and VEGF negative group are significant (P<0.05), whereas the differences of the survival rates among the HIF-1α negative group and positive group are not significant (P>0.05).

CONCLUSION: HIF-1α plays important roles in neovascularization in HCC possibly through regulation of VEGF transcription.

Influence of VEGF and Ki-67 expression on biological behavior of gastric cancer

AIM: To investigate the relationship between expression of vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen Ki-67 and the biological behavior of gastric cancer.

METHODS: The Ki-67 labeling index (Ki-67-LI)and VEGF expression in tumors were analyzed by immunohistochemistry using specific antibodies. The relationship between each other, and their prognostic significance were evaluated.

RESULTS: The intensity of VEGF staining was correlated with tumor maximum diameter (P = 0.011), depth of tumor invasion (P = 0.014), lymph node metastasis (P = 0.017) and tumor stage (P = 0.001). The Ki67-LI of VEGF positive group (562.8±118.3) was significantly higher than that of negative group (436.8±142.2)(P = 0.0 005). The prognosis of VEGF positive group was significantly worse than that of negative group. Ki67-LI was significantly correlated with lymph node metastasis(P = 0.027), tumor stage (P = 0.020) and prognosis(P = 0.036).

CONCLUSION: VEGF promotes tumor angiogenesis and development. High Ki67-LI reflects active proliferation of tumor cells. Both indicate an unfavorable prognosis.

Expression of urokinase-type plasminogen activator system and vascular endothelial growth factor in human gastric cancer and the relationship with tumor invasion and metastasis

AIM: To detect the expression of urokinase-type plasminogen activator (uPA), uPA receptor (uPAR), plasminogen activator inhibitor type 1 (PAI-1) and vascular endothelial growth factor (VEGF) in human gastric cancer (GC) and to reveal their correlation to the major clinicopathological characteristics including tumor invasion and metastasis.

METHODS: Expression of uPA, uPAR, PAI-1 and VEGF was examined in the tissue sections from 67 cases of human GC using streptoavidin-biotin-peroxidase immunohistochemistry method.

RESULTS: The expression of uPA, uPAR, PAI-1 and VEGF was mainly located in the cytoplasm of GC cells. The expression of uPA, uPAR, PAI-1 and VEGF in GC was significantly higher than in the cancer-adjacent tissue (P<0.01). The expression of uPA, uPAR, PAI-1 and VEGF in GC with serosa invasion was significantly higher than that in cancer without serosa invasion (P<0.05). Positive rates of staining for uPA and uPAR in GC with lymph node metastasis were significantly higher compared to cancer without lymph node metastasis (P = 0.002 and 0.008 respectively). The expression of PAI-1 was significantly associated with the differentiation degree of cancer (P<0.01), while no relationship was found between the expression of uPA, uPAR, VEGF and the differentiation degree of cancer. The expression of uPA was correlated with uPAR in cancer tissue(r = 0.653, P<0.001). In 41 cases positive for uPA and uPAR, 28 were with lymph node metastasis (P<0.01, compared with 4/15). Positive correlation was observed between the expression of uPA and VEGF protein (r = 0.300, P<0.05), and between PAI-1 and VEGF (r = 0.413, P< 0.01). Multivariate Cox regression analysis indicated that only the depth of invasion, the expression of uPA and the differentiation affected lymph node metastasis in GC.

CONCLUSION: Expression of uPA, uPAR, PAI-1 and VEGF protein is increased in gastric cancer. uPA and uPAR may play an important role in the invasion and metastasis through VEGF which promotes angiogenesis.

Expression of TNF-α and VEGF in the esophagus of portal hypertensive rats

AIM: To investigate the expression of tumor necrosis factor-alpha (TNF-α) and vascular endothelial growth factor (VEGF) in the development of esophageal varices in portal hypertensive rats.

METHODS: Thirty male Sprague-Dawley (SD) rats in the model group in which a two-stage ligation of portal vein plus ligation of the left adrenal vein was performed, were divided into three subgroups (M₇, M₁₄, and M₂₁) in which the rats were kiued on the seventh day, the 14^th d and the 21 d after the complete portal ligation. Thirty male SD rats, which underwent the sham operation in the control group, were also separated into three subgroups (C₇, C₁₄ and C₂₁) corresponding to the models. The expression of TNF-α and VEGF in the esophagus of all the six subgroups of rats were measured with immunohistochemical SP technique.

RESULTS: The portal pressure in the three model subgroups was significantly higher than that in the corresponding control subgroups (23.82±1.83 vs 11.61±0.86 cmH₂O, 20.90±3.27 vs 11.43±1.55 cmH₂O and 20.68±2.27 vs 11.87±0.79 cmH₂O respectively, P<0.01), as well as the number (9.3±1.6 vs 5.1±0.8, 11.1±0.8 vs 5.4±1.3 and 11.7±1.5 vs 5.2±1.1 respectively, P<0.01) and the total vascular area (78972.6±3527.8 vs 12993.5±4994.8 μm², 107207.5±46461.4 vs 11862.6±5423.2 μm² and 110241.4±49262.2 vs 11973.7±3968.5 μm² respectively, P<0.01) of submucosal veins in esophagus. Compared to the corresponding controls, the expression of TNF-α and VEGF in M₂₁ was significantly higher (2.23±0.30 vs 1.13±0.28 and 1.65±0.38 vs 0.56±0.30 for TNF-α and VEGF respectively, P <0.01), whereas there was no difference in M₇ (1.14±0.38 vs 1.06±0.27 and 0.67±0.35 vs 0.50±0.24 for TNF-α and VEGF respectively, P>0.05) and M₁₄ (1.20±0.25 vs 1.04±0.26 and 0.65±0.18 vs 0.53±0.25 for TNF-α and VEGF respectively, P>0.05). And the expression of TNF-α and VEGF in M₂₁ was significantly higher than that in M₇ (2.23±0.30 vs 1.14±0.38 and 1.65±0.38 vs 0.67±0.35 for TNF-α and VEGF respectively, P<0.01) and M₁₄ (2.23±0.30 vs 1.20±0.25 and 1.65±0.38 vs 0.65±0.18 for TNF-α and VEGF respectively, P<0.01), but there was no difference between M₇ and M₁₄ (1.14±0.38 vs 1.20±0.25 and 0.67±0.35 vs 0.65±0.18 for TNF-α and VEGF respectively, P >0.05).

CONCLUSION: In the development of esophageal varices in portal hypertensive rats, increased TNF-α and VEGF may be not an early event, and probably play a role in weakening the esophageal wall and the rupture of esophageal varices.

Immunohistochemical assessment of angiogenesis in hepatocellular carcinoma and surrounding cirrhotic liver tissues

AIM: To investigate whether vascular endothelial growth factor (VEGF) was over-expressed in hepatocellular carcinoma (HCC) or in surrounding cirrhotic liver tissues.

METHODS: Immunohistochemistry was performed to investigate the expression of VEGF proteins in HCC tissues from 105 consecutive patients undergoing curative resection for HCC. The immunostaining results and related clinicopathologic materials were analyzed with statistical methods. Kaplan–Meier method was used to calculate survival curves, and Log-rank test was performed to compare differences in survival rates of the patients with positive HCC staining and negative VEGF.

RESULTS: VEGF-positive expression was found in 72 of 105 HCC patients (68.6%). Capsular infiltration (P = 0.005), vascular invasion (P = 0.035) and intrahepatic metastasis (P = 0.008) were observed more frequently in patients with VEGF-positive expression than in those with VEGF-negative expression. Kaplan–Meier curves showed that VEGF-positive expression was associated with a shorter overall survival (P = 0.014). VEGF-positive expression was found in 47 of tissues 68 HCC (69.1%), and VEGF-positive expression was found in 54 of 68 surrounding cirrhotic liver tissues (79.4%). VEGF-positive expression was significantly higher in surrounding cirrhotic liver tissues than in HCC (P = 0.017).

CONCLUSION: VEGF may play an important role in the angiogenesis and prognosis of HCC, as well as in the angiogenesis of liver cirrhosis.

Activation of STAT3 signaling in human stomach adenocarcinoma drug-resistant cell line and its relationship with expression of vascular endothelial growth factor

AIM: To investigate the difference in activation of STAT3 signaling between two human stomach adenocarcinoma cell lines: 5-fluorouracil resistant cell line and its parental cell line, and to evaluate its relationship with the expression of vascular endothelial growth factor (VEGF).

METHODS: Western blot and electrophoretic mobility shift assay (EMSA) were used to detect the expression of phospho-STAT3 protein and constitutive activation of STAT3 in two human stomach adenocarcinoma cell lines, 5-fluorouracil resistant cell line SGC7901/R and its parental cell line SGC7901, respectively. The mRNA expression of VEGF was analysed by semi-quantitative RT-PCR. The expressive intensity of VEGF protein was measured by immunocytochemistry.

RESULTS: The expressions of phospho-STAT3 protein and constitutive activation of STAT3 between two human stomach adenocarcinoma cell lines were different. Compared with the parental cell line SGC7901, the STAT3-DNA binding activity and the expressive intensity of phospho-STAT3 protein were lower in the drug-resistant cell line SGC7901/R. The expression levels of VEGF mRNA and its encoded protein were also decreased in drug-resistant cell line.

CONCLUSION: Over-expression of VEGF may be correlated with elevated STAT3 activation in parental cell line. Lower VEGF expression may be correlated with decreased STAT3 activation in resistant cell line, which may have resulted from negative feedback regulation of STAT signaling.

Tumor angiogenesis and its clinical significance in pediatric malignant liver tumor

AIM: To investigate the expression of vascular endothelial growth factor (VEGF) and microvascular density (MVD) count in pediatric malignant liver tumor and their clinical significances.

METHODS: Fourteen children with malignant liver tumors including seven hepatocellular carcinomas (HCCs), five hepatoblastomas, one malignant mesenchymoma and one rhabdomyosarcoma were studied. Twelve adult HCC samples served as control group. All samples were examined with streptavidin-biotin peroxidase (SP) immunohistochemical staining for VEGF expression and MVD count.

RESULTS: VEGF positive expression in all pediatric malignant liver tumors was significantly higher than that in adult HCC (0.4971±0.14 vs 0.4027±0.03, P<0.05). VEGF expression in pediatric HCC group was also markedly higher than that in adult HCC group (0.5665±0.10 vs 0.4027±0.03, P<0.01) and pediatric non-HCC group (0.5665±0.10 vs 0.4276±0.15, P<0.05). The mean value of MVD in pediatric malignant liver tumors was significantly higher than that in adult HCC (33.66±12.24 vs 26.52±4.38, P<0.05). Furthermore, MVD in pediatric HCC group was significantly higher compared to that in adult HCC group (36.94±9.28 vs 26.52±4.38, P<0.05), but there was no significant difference compared to the pediatric non-HCC group (36.94±9.28 vs 30.37±14.61, P>0.05). All 7 children in HCC group died within 2 years, whereas the prognosis in pediatric non-HCC group was better, in which two patients survived more than 5 years.

CONCLUSION: Children with malignant liver tumors, especially with HCC, may have extensive angiogenesis that induces a rapid tumor growth and leads to a poor prognosis.

Expression of c-kit and p53 in non-small cell lung cancers

PURPOSE

Increasing experimental evidence indicates that abnormal expression of c-kit may be implicated in the pathogenesis of a variety of solid tumors. It has been reported that over 70% of small cell lung cancer (SCLC) contain the c-kit receptor. In the present study, a c-kit analysis has been extended to non-small cell lung cancer (NSCLC). The expressions of p53, vascular endothelial growth factor (VEGF) and cd34, in addition to c-kit, were evaluated to investigate the correlations between these proteins and to determine their potential relationships with the clinicopathological data.

MATERIALS AND METHODS

Paraffin-embedded tumor sections, obtained from 147 patients with NSCLC, were immunohistochemically investigated using anti-c-kit, anti-p53, anti-VEGF and anti-cd34 antibodies.

RESULTS

c-kit was expressed in 40 (27%) of the tumors examined: 27% of the adenocarcinomas, 27% of the squamous cell carcinomas and 29% of the undifferentiated carcinomas. p53 and VEG F immunoreactivities were present in 107 (73%) and 110 (75%) carcinomas, respectively. Anti-cd34 was negative in all samples. No associations were established among these proteins. The c-kit, however, showed a strong correlation with the T factor: T1 (n=11), 0%; T2 (n=49), 16% and T3 (n=87), 37% (p=.006).

CONCLUSION

It is suggested that in NSCLC c-kit is expressed relatively frequently and may become a therapeutic target for the patients with inoperable or recurrent c-kit positive tumors. The alterations in p53 probably constitute an early event, whereas the activated c-kit may contribute to tumor progression.

Clinical Implications of VEGF and p53 Expression in Squamous Cell Carcinoma of the Cervix Treated with Radiation Therapy

PURPOSE

The present study was designed to analyze the relationship between vascular endothelial growth factor (VEGF) and p53, and their impact on clinical outcome in squamous cell carcinoma of the cervix treated with radiation therapy.

MATERIALS AND METHODS

This immunohistochemical study involved 23 patients with available paraffin blocks among 46 patients who were treated during the period from 1994 to 1997 in Eulji University Hospital in Korea. Anti-VEGF mouse monoclonal antibody and DO-7 anti- p53 mouse monoclonal antibody were used as the primary antibodies. Antibody binding was detected with a LSAB kit. Staining was defined as positive for VEGF and p53, when more than 10% and 5% of the tumor cells were stained out of 500 cells counted, respectively.

RESULTS

FIGO stage (p=0.05) and tumor size (p=0.04) were significant prognostic factors for survival. p53 expression was present in 17 (77%) cases. There was no significant relationship between p53 staining and the clinicopathologic factors, such as FIGO stage (p=0.98), tumor size (p=0.43), lymph node status (p=0.82), parametrial invasion (p=0.96), and age (p=0.18). The five year survival rates according to the p53 expression status were 80% for the p53 negative group and 66% for the p53 positive group (p=0.58). Positive VEGF expression was observed in 11 (47%) of the total of 23 patients. Statistical evaluation of VEGF expression according to stage (p=0.36), tumor size(p=0.11), lymph node status (p=0.82), parametrial invasion (p=0.49), and age (p=0.55) revealed no significant difference in any of these parameters. The five year survival rates according to the VEGF expression status were 89% for the VEGF negative group and 41% for the VEGF positive group (p=0.07).

CONCLUSION

We suggest that VEGF expression may have an effect on the prognosis of cervix cancer patients treated with radiation therapy, and further evaluation with a large sample size is warranted.

Prognostic Effect of Vascular Endothelial Growth Factor and Angiogenesis in Gastric Carcinoma

PURPOSE

Many studies have shown that angiogenesis has an important role in the growth, progression, and metastasis of solid tumors. Recently, several angiogenic factors have been identified. Vascular endothelial growth factor (VEGF) is a well characterized inducer of angiogenesis. In this study, we investigated the prognostic significance of the expression of VEGF in patients with an advanced gastric carcinoma.

MATERIALS AND METHODS

Specimens from 54 gastric adenocarcinoma patients were stained using a polyclonal antibody against VEGF. Correlations of the expression of VEGF, microvessel density, and various other clinicopathological factors were analysed.

RESULTS

Seventeen (31.5%) and 37 cases (68.5%) were VEGF-negative and positive, respectively. There was significant correlation between the expression of VEGF and pathological differentiation. There were no significant correlations between the expression of VEGF, stage and recurrence of a gastric carcinoma. The microvessel density was significantly higher in the VEGF-positive than the VEGF-negative tumors. Survivals of the VEGF-negative patients were significantly prolonged compared to those of the VEGF-positive patients.

CONCLUSION

The results of this study show that the expression of VEGF may be a useful prognostic factor for patients with a gastric adenocarcinoma.

Expression of vascular endothelial growth factor in normal pituitary cells and pituitary adenomas producing adrenocorticotropic hormone

Vascular endothelial growth factor (VEGF) induces endothelial cell proliferation and an increase in capillary permeability. Because the anterior pituitary gland and pituitary adenomas are highly vascular, expression of VEGF was examined immunohistochemically. Some normal pituitary cells stained positively for VEGF, and restaining for ACTH, prolactin, TSH, LH, FSH, and S-100 protein after VEGF staining revealed that almost all cells staining positively for ACTH also stained for VEGF. Only adenomas staining positively for ACTH stained for VEGF. These results suggest that VEGF is produced by normal pituitary cells and adenomas producing ACTH.