Expression of vascular endothelial growth factor C and D (VEGF-C and -D) is an important risk factor for lymphatic metastasis in undifferentiated early gastric carcinoma

Mechanisms Underlying Therapeutic Effects Of Traditional Chinese Medicine On Gastric Cancer

Gastric cancer (GC) is one of the most common malignant tumors in the world. It is the fourth most common cancer and has the second highest mortality rate globally. Metastasis is an important feature of gastric cancer and is the most common cause of death. Exploring the mechanism underlying the metastasis of gastric cancer and searching for new drug targets has become the focus of several studies. Traditional Chinese medicine may show promise for treatment of gastric cancer. In this review, we report the recent progress in research on the anti-metastasis activity of Chinese medicine, to facilitate clinical development of treatments for gastric cancer.

Effect of vascular endothelial growth factor-C expression on lymph node metastasis in human cholangiocarcinoma

The present study aimed to evaluate the expression of vascular endothelial growth factor C (VEGF-C) in human cholangiocarcinoma tissues and its role in metastasis in vitro. A total of 65 biopsy samples of cholangiocarcinoma, plus the FRH-0201 cell line, were investigated. The expression of VEGF-C in the human cholangiocarcinoma specimens was evaluated by immunohistochemistry (IHC). The effect of VEGF-C on tumor cell migration and proliferation was measured by MTT and Transwell assays in the FRH-0201 cell line. According to the IHC results, the biopsies of human cholangiocarcinoma were stained positively for VEGF-C, with a positive rate of 75.4% (49/65). Moreover, VEGF-C was expressed at a higher level in the patients with lymph node metastasis than in those without lymph node metastasis. In vitro, VEGF-C exhibited marked growth stimulation below the concentration of 5 ng/ml and was able to promote cholangiocarcinoma cell migration significantly. These findings suggested that VEGF-C may be a useful factor to predict lymph node metastasis in cholangiocarcinoma tissues and indicates that VEGF-C plays a significant role in proliferation and migration in cholangiocarcinoma cells.

Genetic Identification of SEMA3F as an Antilymphangiogenic Metastasis Suppressor Gene in Head and Neck Squamous Carcinoma

Head and neck squamous cell carcinomas (HNSCC) often metastasize to locoregional lymph nodes, and lymph node involvement represents one of the most important prognostic factors of poor clinical outcome. HNSCCs are remarkably lymphangiogenic and represent a clear example of a cancer that utilizes the lymphatic vasculature for malignant dissemination; however, the molecular mechanisms underlying lymphangiogenesis in HNSCC is still poorly understood. Of interest, we found that an axon guidance molecule, Semaphorin 3F (SEMA3F), is among the top 1% underexpressed genes in HNSCC, and that genomic loss of SEMA3F correlates with increased metastasis and decreased survival. SEMA3F acts on its coreceptors, plexins and neuropilins, among which neuropilin-2 (NRP2) is highly expressed in lymphatic endothelial cells (LEC) but not in oral epithelium and most HNSCCs. We show that recombinant SEMA3F promotes LEC collapse and potently inhibits lymphangiogenesis in vivo. By reconstituting all possible plexin and neuropilin combinations, we found that SEMA3F acts through multiple receptors, but predominantly requires NRP2 to signal in LECs. Using orthotopic HNSCC metastasis mouse models, we provide direct evidence that SEMA3F re-expression diminishes lymphangiogenesis and lymph node metastasis. Furthermore, analysis of a large tissue collection revealed that SEMA3F is progressively lost during HNSCC progression, concomitant with increased tumor lymphangiogenesis. SEMA3F is localized to 3p21, an early and frequently deleted locus in HNSCC and many other prevalent human malignancies. Thus, SEMA3F may represent an antilymphangiogenic metastasis suppressor gene widely lost during cancer progression, hence serving as a prognostic biomarker and an attractive target for therapeutic intervention to halt metastasis.

[Inhibitory effect of endostar on lymphangiogenesis in non-small cell lung cancer and its effect on circulating tumor cells]

背景与目的

血管内皮抑素可以抑制肿瘤新生血管的生成，但对肿瘤微淋巴管的形成与发展是否存在抑制效应引起我们关注。本研究旨在探讨重组人血管内皮抑素（recombinant human endostatin injection）对非小细胞肺癌组织中血管内皮生长因子（vascular endothelial growth factor, VEGF）-C、VEGF-D和VEGF受体（VEGFR）-3表达及对外周血循环肿瘤细胞数目的影响。

方法

荷瘤裸鼠随机分为空白对照组、顺铂组、不同浓度重组人血管内皮抑素组及重组人血管内皮抑素+顺铂组，连续给药2周。1周后检测肿瘤组织中VEGF-C、VEGF-D、VEGFR-3的表达水平和微淋巴管密度。免疫荧光染色诊断和计数循环肿瘤细胞。

结果

重组人血管内皮抑素组与重组人血管内皮抑素联合顺铂组的表达阳性率、微淋巴管密度均明显低于空白对照组与顺铂组（P < 0.05）；较高浓度的重组人血管内皮抑素联合顺铂组与重组人血管内皮抑素组表达阳性率和微淋巴管密度低于相应较低重组人血管内皮抑素浓度的组别（P < 0.05）。各组微淋巴管密度与VEGF-C、VEGF-D、VEGFR-3表达阳性率存在正相关。重组人血管内皮抑素联合顺铂各组的循环肿瘤细胞数目明显低于单独使用顺铂或重组人血管内皮抑素（P < 0.05）。

结论

重组人血管内皮抑素可以抑制肿瘤新生淋巴管生成，减少循环肿瘤细胞，作用大小与浓度有关。与顺铂联合使用能够更有效的减少循环肿瘤细胞。

Anti-angiogenic therapies for advanced esophago-gastric cancer

Neo-vascularization is a vital process for tumor growth and development which involves the interaction between tumor cells and stromal endothelial cells through several growth factors and membranous receptors which ultimately activate pro-angiogenic intracellular signaling pathways. Inhibition of angiogenesis has become a standard treatment option for several tumor types including colorectal cancer, glioblastoma and ovarian cancer. In gastric cancer, the therapeutic role of anti-angiogenic agents is more controversial. Bevacizumab and ramucirumab, two monoclonal antibodies, which target vascular endothelial growth factor-A and vascular endothelial growth factor receptor-2, respectively, have been demonstrated antitumor activity in patients with tumors of the stomach or esophagogastric junction. However, especially for bevacizumab, this antitumor activity has not consistently translated into a survival advantage over standard treatment in randomized trials. In this article, we provide an overview of the role of angiogenesis in gastric cancer and discuss the results of clinical trials that investigated safety and effectiveness of antiangiogenic therapies in this disease. A review of the literature has been done using PubMed, ClinicalTrials.gov website and the ASCO Annual Meeting Library.

Expression levels of vascular endothelial growth factors a and C in patients with peptic ulcers and gastric cancer

Purpose

Vascular endothelial growth factor (VEGF) is one of the most important growth factors for metastatic tumors. To clarify the role of VEGF-A and C in patients with peptic ulcer disease (PUD) or gastric cancer (GC), we evaluated the expression levels of these two molecules. We also analyzed the effect of Helicobacter pylori infection on VEGF-A and C expression levels.

Materials and Methods

Patients with dyspepsia who needed diagnostic endoscopy were selected and divided into three groups: non-ulcer dyspepsia (NUD), PUD, and GC, according to their endoscopic and histopathological results. Fifty-two patients with NUD, 50 with PUD, and 38 with GC were enrolled in this study. H. pylori infection was diagnosed by the rapid urease test. After RNA extraction and synthesis of cDNA, the expression levels of VEGF-A and C were determined by quantitative reverse transcriptase polymerase chain reaction.

Results

The VEGF-C expression level in the PUD and GC groups was significantly higher than that in the NUD group. Moreover, the VEGF-A expression level in the PUD and GC groups was higher than in the NUD group, although the differences were not statistically significant. Significant positive correlations were also observed between the expression levels of these two molecules in the PUD and GC groups. In addition, the expression levels of these two molecules were higher in H. pylori positive patients with PUD or GC than in H. pylori negative patients of the same groups; however, these differences did not reach statistical significance.

Conclusions

Up-regulation of VEGF-C expression during gastric mucosal inflammation may play a role in the development of peptic ulcers or GC.

The biophysical property of A549 cells transferred by VEGF-D

Vascular endothelial growth factor-D (VEGF-D) together with VEGF-C is considered to be associated with lymphangiogenesis and angiogenesis and involve in tumorization. This study aims to investigate the influence of exogenous VEGF-D gene on the biophysical property of cell surface of lung adenocarcinoma cell line. A panel of lung adenocarcinoma cell lines were examined the expression of VEGF-D and VEGF-C by real-time PCR. The VEGF-D recombinant plasmid containing enhanced green fluorescence protein (EGFP) was constructed and transfected to the cell line with no expression of VEGF-D and confirmed by real-time PCR and Western blot analysis. Topographic images of cells were obtained by using atomic force microscope (AFM) in contact mode. Unlike VEGF-C, VEGF-D was found to have a very low expression or undetectable expression in lung adenocarcinoma cell lines. The VEGF-D recombinant plasmid had been constructed successfully and was transferred into the human lung adenocarcinoma cell line A549 cells which had no endogenous expression of VEGF-D, and exogenous VEGF-D could be detected in mRNA and protein expression levels in the gene modified cells, while the VEGF-C gene expression had no change after VEGF-D transfection. After transfection, the irregular microspikes or nano clusters could observe on the surface of A549 cells, and VEGF-D transfected A549 cells became more rigid. The exogenous VEGF-D gene might cause the remarkable biophysical architectural changes in the A549 cells, which might as a novel biomarker for evaluation of its biological function.

Quantitative analysis of VEGF-C mRNA of extrahepatic cholangiocarcinoma with real-time PCR using samples obtained during endoscopic retrograde cholangiopancreatography

OBJECTIVE

Vascular endothelial growth factor (VEGF)-C overexpression in extrahepatic cholangiocarcinoma (ECC) has been shown to be correlated with lymph node metastasis. The intensity of immunohistochemical staining of VEGF-C protein in surgical samples has been used as index of VEGF-C overexpression in previous studies. The aim of the study was to examine if VEGF-C overexpression in ECC could be preoperatively detected by using samples obtained during ERCP.

METHODS

Consecutive patients who underwent endoscopic retrograde cholangiopancreatography (ERCP) for biliary stricture during the study period were prospectively analyzed. VEGF-C mRNA was quantified by real-time PCR methods using endoscopic samples obtained during ERCP. The high intensity of immunohistochemical staining of VEGF-C protein in surgical samples was used for the reference standard of VEGF-C overexpression. The level of S100P mRNA which was a novel diagnostic marker of ECC was also quantified to evaluate whether the endoscopic samples contained ECC cells.

RESULTS

Twenty-five patients were enrolled in this study. Eighteen patients were diagnosed as ECC and seven patients were diagnosed as benign biliary structure. Nine of eighteen patients with ECC, who showed positive S100P mRNA in endoscopic samples and received surgical resection, were finally analyzed. Receiver operating characteristics analysis yielded VEGF-C mRNA cut-off value of 3.85 for detection of VEGF-C overexpression, and the diagnostic performance of VEGF-C mRNA measurement in the endoscopic sample for VEGF-C overexpression reached sensitivity of 75.0%, specificity of 100%, and accuracy of 88.9%.

CONCLUSION

The quantification of VEGF-C mRNA of ECC with real-time PCR using endoscopic samples was useful for preoperative detection of VEGF-C overexpression.

Tumor interstitial fluid and gastric cancer metastasis: an experimental study to verify the hypothesis of "tumor-phlegm microenvironment"

OBJECTIVE

To extract tumor interstitial fluid (TIF) from MKN-45 gastric cancer which is similar to "muddy phlegm" in Chinese medicine and observe influences of MKN-45 tumor interstitial fluid (MKN-45 TIF) intervention on metastasis of gastric cancer and on the expressions of vascular endothelial growth factor (VEGF), kinase insert domain containing receptor (KDR), epithelial-cadherin (E-cad), cyclooxygenase-2 (COX-2), intercellular adhesion molecule-1 (ICAM-1) and telomerase genes and proteins in primary tumor tissue.

METHODS

An MKN-45 tumor-bearing model was established in 50 nude mice. The modeled animals were equally randomized to 5 groups: the simple tumor-bearing group (model group), the normal saline (NS) via tail vein injection (i.v.) group (NS i.v. group), MKN-45 TIF i.v. group (TIF i.v. group), NS intraperitoneal injection (i.p.) group (NS i.p. group), and MKN-45 TIF i.p. group (TIF i.p. group). The TIF and NS intervention groups received injection (i.p. or i.v.) of MKN-45 TIF or NS twice a week, 0.2 mL at a time. After 8 weeks, the primary tumors were removed, weighed and HE stained to observe tumor metastasis. The primary tumor tissues were analyzed by immunohistochemistry and real-time quantitative PCR to detect expressions of VEGF, KDR, E-cad, COX-2, ICAM-1, and telomerase genes and proteins in different groups.

RESULTS

There were significant differences in tumor weight between TIF intervention groups and the model and NS intervention groups. Tumor metastasis was observed in all 5 groups, but the tumor metastasis rate in TIF intervention groups was significantly higher than those in the model and NS intervention groups. The gene and protein expressions of gastric cancer-related factors VEGF, KDR, COX-2, ICAM-1 and telomerase were unregulated while the gene and protein expressions of E-cad were downregulated in TIF intervention groups.

CONCLUSIONS

TIF promotes tumor growth, invasion and metastasis of gastric cancer. These findings provide preliminary experimental clues for verifying the hypothesis of "tumor-phlegm microenvironment".

Lymphangiogenesis in cancers: A therapy target

Tumor metastasis is a major cause of death among cancer patients. The lymphatic vasculature is an important route for the metastatic spread of cancer. Recent research has indicated that vascular endothelial growth factor C (VEGF-C), VEGF-D and VEGF receptor-3 (VEGFR-3) are closely related to tumor-induced lymphangiogenesis, tumor metastasis and prognosis. Numerous studies demonstrate that the VEGF-C/VEGF-D/VEGFR-3 signaling axis plays a leading role in the regulation of tumor lymphangiogenesis and is related to tumor metastasis and prognosis. It has been confirmed that inhibition of the VEGF-C/VEGF-D/VEGFR-3 signaling axis can exert anti-lymphangiogenic effect and thereby prevent tumor metastasis in animal models. In this paper we review the molecular biology of lymphangiogenesis, its relationship with cancer metastasis, and the clinical implications of inhibition of lymphangiogenesis.

VEGF-C as a decision-making biomarker for selected patients with invasive bladder cancer who underwent bladder-preserving radical surgery

BACKGROUND AND AIMS

We proved the feasibility of radical transurethral resection in selected patients with muscle-invasive bladder cancer with a minimum follow-up of >5 years. A follow-up schedule was developed based on progression and recurrence during this period.

METHODS

The study included 93 patients with invasive bladder cancer treated by radical transurethral resection. Student t test was used for continuous variables to establish clinical progression predictive factors. VEGF-C protein expressions were tested by immunohistochemistry postsurgery.

RESULTS

The overall survival and disease-specific survival rates for all 93 patients were 59.1% and 65.2%, respectively. The clinical stage of the tumor influenced overall survival (p = 0.024) and disease-specific survival (p = 0.047). A significantly higher overall survival and disease-specific survival rate for patients with low levels of VEGF-C was 69.6% and 75.0%, respectively, than for those with high levels of VEGF-C (45.9 and 54.1%, respectively, p <0.05).The presence of bladder Tis reduced the survival rate (41.2 vs. 65.3%) and disease-specific survival (45.4 vs. 72.1%). Sensitivity, specificity and accuracy of VEGF-C in the evaluation of disease progression were 76.7, 77.8, 77.4%, respectively.

CONCLUSIONS

Patients with T2 stage, low level of VEGF-C and absence of bladder Tis were associated with high overall survival and disease-specific survival rate. VEGF-C level can evaluate disease progression and assist in choosing the appropriate treatment.

Role of lymphangiogenesis in lung cancer

Lung cancer represents one of the most frequent causes of death due to neoplastic disease in Poland and around the world. The high mortality which accompany neoplastic diseases used to be ascribed mainly to dissemination of cancerous cells. Studies on animal models suggest that tumour lymphangiogenesis represents the principal factor in the process of metastases formation. Lymphangiogenesis involves a process of formation of new lymphatic vessels from already existing lymphatic capillaries. Lymphangiogenesis is stimulated by vascular endothelial growth factors (VEGF) and other, recently reported factors, such as, e.g., cyclooxygenase 2, fibroblast growth factor 2, angiopoetin-1 and the insulin-resembling growth factor. In lymphangiogenesis a key role is played by neutropilin 2 or podoplanin and this promoted development of studies on lymphangiogenesis. Activation of VEGF-C/VEGF-D/VEGFR-3 axis increases motility and invasiveness of neoplastic cells, promotes development of metastases in several types of tumours such as, e.g., lung cancer, mammary carcinoma, cancers of the neck, prostate and large intestine. In recent years lymphangiogenesis provided topic of many studies. A positive correlation was detected between expressions of VEGF-C/D and VEGFR-3 in non-small cell lung cancer. In patients with lung cancer with high expression of VEGF-C a markedly abbreviated survival was noted. Positive correlation was detected between expression of VEGF-C and VEGF-D on one hand and expression of LYVE-1 on the other in sentinel lymph nodes with metastases of neoplastic cells in patients with non-small cell lung cancer. Also, high density of lymphatic vessels and high density of intraneoplastic microvessels proved to be independent poor prognostic indices in patients with non-small cell lung cancer. Extensive hope is linked to studies on inhibitors of lymphangiogenesis, which may improve results of treatment also in tumour patients.

Vascular endothelial growth factor-D is correlated with hepatic metastasis from gastric cancer after radical gastrectomy

BACKGROUND

Vascular endothelial growth factor-D (VEGF-D), the activating ligand for vascular endothelial growth factor receptor-3 (VEGFR-3), has been identified as an important endogenic tumor-associated lymphangiogenic factors which can promote lymphatic metastasis from primary tumor. Lymphatic metastasis, which is the most common metastatic method of gastric cancer (GC), is still deemed a potentially relative indicator of distant metastasis from GC. We hypothesize that VEGF-D is associated with hepatic metastasis (HM) from GC after radical gastrectomy by promoting lymphatic metastasis and/or hematogenous metastasis.

METHODS

This study included 150 GC patients who underwent radical gastrectomy (75 cases presented with HM and 75 cases presented without any recurrences). VEGF-D, VEGF-C, VEGF-A, VEGFR-2, VEGFR-3, and microvessel density (MVD) were evaluated by immunohistochemistry. Besides, clinicopathologic variables and prognosis of GC patients were analyzed statistically.

RESULTS

Significant associations were seen between Lauren classification and HM, VEGF-D and HM, VEGFR-3 and HM, MVD and HM, and between nodal status and HM. VEGF-D remained an independent factor for HM from GC after radical gastrectomy. Further significant association was evaluated between high-grade VEGF-D expression and short disease-free survival of HM from GC after radical gastrectomy.

CONCLUSION

VEGF-D, which can induce lymphangiogenesis specifically in many kinds of malignant diseases, is an important factor for predicting HM from GC following radical gastrectomy.

Vascular endothelial growth factor-C and -D expression correlates with lymph node micrometastasis in pN0 early gastric cancer

BACKGROUND AND OBJECTIVES

Vascular endothelial growth factors (VEGF)-C and -D play an important role in lymphangiogenesis, and the expressions of these factors are related to lymphatic invasion and lymph node metastasis in various malignant neoplasms. The present study investigates the expression of VEGF-C and -D in early gastric cancer and analyzes its relationship to lymph node micrometastasis determined by reverse transcription-polymerase chain reaction (RT-PCR).

METHODS

We examined 1,828 lymph nodes obtained from 80 patients with node-negative early gastric cancer. All dissected lymph nodes were examined by RT-PCR for CEA mRNA in addition to hematoxylin-eosin staining. The resected primary specimens were immunostained using anti-VEGF-C and -D polyclonal antibodies.

RESULTS

The incidence of lymph node micrometastasis determined by RT-PCR was 23.8% (19/80). The high expression of VEGF-C and -D was found in 27.5% (22/80) and in 21.3% (17/80), respectively. The expression of VEGF-C and -D was closely related to lymph node micrometastasis (P = 0.0390 and 0.0213, respectively).

CONCLUSIONS

We demonstrated a close relationship between micrometastasis and VEGF-C and -D expression of the primary tumor. Thus, levels of VEGF-C and -D expression might be useful for predicting micrometastasis in patients with early gastric cancer.

Correlation of vascular endothelial growth factor-D expression and VEGFR-3-positive vessel density with lymph node metastasis in gastric carcinoma

Lymph node metastasis is an important prognostic factor in gastric cancer. Vascular endothelial growth factor-D (VEGF-D) is a lymphangiogenic growth factor that activates VEGF receptor (VEGFR)-3, a receptor expressed in the lymphatic endothelium. We investigated the clinical value of VEGF-D expression and VEGFR-3 positive vessel density in gastric carcinoma with regard to lymphangiogenesis. Immunohistochemical staining was used to determine the expression of VEGF-D and VEGFR- 3 in specimens from 104 cases of resected gastric cancer. VEGF-D expression was observed in 62.5% of the gastric cancers and in 9.6% of the non-neoplastic gastric tissue. The VEGFR-3-positive vessel density was significantly greater in the VEGFD positive group than the negative group. VEGF-D expression was significantly associated with lymph node metastasis, increased serum CEA levels, and the nonsignet ring cell type. The VEGFR-3-positive vessel density was correlated with tumor size, lymphatic invasion, and lymph node metastasis. The VEGF-D expression and high VEGFR-3-positive vessel density were significant poor prognostic factors for relapse-free survival. These results suggest that VEGF-D and VEGFR-3-positive vessel density are potential molecular markers that predict lymphatic involvement in gastric carcinoma.

Tumor lymphangiogenesis and melanoma metastasis

Malignant melanomas of the skin primarily metastasize to lymph nodes, and the detection of sentinel lymph node metastases serves as an important prognostic parameter. There is now compelling evidence that melanomas can induce lymphangiogenesis (growth of lymphatic vessels), mainly at the tumor-stroma interface, and that the level of tumor lymphangiogenesis is correlated with the incidence of sentinel lymph node metastases and with disease-free survival. Thus, tumor lymphangiogenesis can serve as a novel prognostic predictor in melanoma. Vascular endothelial growth factor (VEGF)-C, released by melanoma cells and by tumor-associated macrophages, likely represents the major lymphangiogenic factor in melanoma, although other members of the VEGF family might also be involved. The recent discovery that tumors can induce a premetastatic niche, by inducing lymphatic vessel growth in sentinel lymph nodes even before metastasis, and that lymph node lymphangiogenesis enhances metastatic spread, indicates that activated lymphatic vessels represent novel targets for the detection and/or therapy of melanoma metastases.

Circulating lymphangiogenic growth factors in gastrointestinal solid tumors, could they be of any clinical significance?

Metastasis is the principal cause of cancer mortality, with the lymphatic system being the first route of tumor dissemination. The glycoproteins VEGF-C and VEGF-D are members of the vascular endothelial growth factor (VEGF) family, whose role has been recently recognized as lymphatic system regulators during embryogenesis and in pathological processes such as inflammation, lymphatic system disorders and malignant tumor metastasis. They are ligands for the VEGFR-3 receptor on the membrane of the lymphatic endothelial cell, resulting in dilatation of existing lymphatic vessels as well as in vegetation of new ones (lymphangiogenesis). Their determination is feasible in the circulating blood by immunoabsorption and in the tissue specimen by immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR). Experimental and clinicopathological studies have linked the VEGF-C, VEGF-D/VEGFR3 axis to lymphatic spread as well as to the clinical outcome in several human solid tumors. The majority of these data are derived from surgical specimens and malignant cell series, rendering their clinical application questionable, due to subjectivity factors and post-treatment quantification. In an effort to overcome these drawbacks, an alternative method of immunodetection of the circulating levels of these molecules has been used in studies on gastric, esophageal and colorectal cancer. Their results denote that quantification of VEGF-C and VEGF-D in blood samples could serve as lymph node metastasis predictive biomarkers and contribute to preoperative staging of gastrointestinal malignancies.

Expression of vascular endothelial growth factors-C and -D correlate with evidence of lymphangiogenesis and angiogenesis in pancreatic adenocarcinoma

BACKGROUND

We analyzed the intratumoral and peritumoral microvessel density (MVD) and microlymphatic vessel density (MLVD) in pancreatic adenocarcinoma (PAC) and recorded the expression of vascular endothelial growth factor (VEGF)-C and -D. These data were tested for their significance for tumor progression.

METHODS

The tissue samples were obtained from 30 patients with PAC. The expression of VEGF-C and -D, MLVD, MVD was assayed by immunohistochemical staining. The expression of VEGF-A and -C, and -D mRNA was detected by semi-quantitative RT-PCR.

RESULTS

Immunohistochemical analysis revealed the presence of VEGF-C and -D immunoreactivity in 73% (22/30) and 57% (17/30). The positive rates of VEGF-C and -D protein in central portion of tumors (30% and 16.7%) were significantly lower than those in marginal portion (73.3% and 56.7%). The group with high expression of VEGF-C and -D in marginal portion had higher incidence of lymph node metastasis, lymphatic invasion and venous invasion. The MLVD in both of the VEGF-C and -D positive groups was higher than that in the negative groups, and the lymph node metastasis increased. MVD in the VEGF-C positive group was higher than that in the negative group.

CONCLUSIONS

The expression of VEGF-C and -D in the marginal portion of tumor significantly associated with lymphatic metastasis and prognosis in patients with PAC, and may induced lymphangiogenesis. VEGF-C was important in the regulation of angiogenesis and lymphangiogenesis in PAC.

Lymph node metastasis in submucosal gastric cancer and reduction surgery

Although the concept of early gastric cancer (EGC) has been accepted, lymph node metastasis is the most important prognostic factor for EGC. Submucosal gastric cancer is greatly concerned because of its high lymph node metastasis incidence accounting for about 20% of all lymph node metastases. Many researchers suggest that reduction surgery should be performed for submucosal gastric cancer patients at a lower risk of developing lymph node metastasis. Submucosal gastric cancer can be divided into 3 levels (Sm1, Sm2, Sm3) based on its depth of invasion, which has been proven useful for predicting lymph node metastasis, directing treatment and evaluating prognosis. Recently, with the advances in clinical pathology and molecular biology, the risk factor for lymph node metastasis of submucosal gastric cancer can be accurately evaluated and its treatment has become rather rational. This paper reviews the relative factors for lymph node metastasis of submucosal gastric cancer and advances in its rational surgical treatment.

Markers of tumour angiogenesis and tumour cells in bone marrow in gastric cancer patients

AIMS

Vascular endothelial growth factors VEGF-A, VEGF-C and VEGF-D are considered to be potentially angiogenetic and lymphangiogenetic. "Minimal residual disease" is responsible for cancer progression and recurrence. In this study, we investigated the relation between expressions of VEGF-A, VEGF-C and VEGF-D in gastric cancer tissue and the presence of tumour cells in bone marrow.

METHODS

A total of 50 resected primary gastric adenocarcinomas, 44 non-cancerous gastric mucosa and 36 lymph node metastases were analyzed by immunohistochemistry for VEGF-A, VEGF-C and VEGF-D. The specimens used were drawn from a previous study cohort, where the presence of ITC in bone marrow was confirmed with immunohistochemical assay with cytokeratin (CK)-18.

RESULTS

The levels of expression of VEGF-A, VEGF-C and VEGF-D were highest in tumour (p < 0.001), and the level in lymph node metastases was significantly higher (p < 0.01) than in mucosa. The expression of VEGF-A was correlated significantly with venous tumour invasion (p < 0.05) and the presence of tumour cells in bone marrow (p < 0.05). Tumours expressing high levels of VEGF-D showed significantly advanced stages of tumour infiltration (p < 0.05) and lymph node metastasis (p < 0.01).

CONCLUSIONS

VEGF-A is a significant marker for the presence of tumour cells in the bone marrow of gastric cancer patients. Our results confirm VEGF-D as a predictor for the lymphatic spread of tumour cells. Therefore, the route of metastatic spread of gastric cancer could be determined, at least in part, by the profile of VEGF family members expressed in the primary tumour of gastric cancer patients.

Vascular endothelial growth factor, hypoxia-inducible factor 1 alpha and CD34 expressions in early-stage gastric tumors: relationship with pathological factors and prognostic impact on survival

BACKGROUND

Angiogenesis is one of the key steps in solid tumor growth and metastasis. We planned to investigate the prognostic significance of vascular endothelial growth factor (VEGF), hypoxia-inducible factor 1alpha (HIF-1alpha) and CD34 expressions as markers of angiogenesis in gastric cancer.

PATIENTS AND METHODS

We retrospectively reviewed the medical records of 51 gastric cancer patients who had total or subtotal gastrectomy at Marmara University Hospital from 1990 to 2004 and evaluated the expression of VEGF, HIF-1alpha and CD34 by immunohistochemistry in their archival tumor tissues. We recorded the clinical and pathological characteristics of these patients and analyzed their survival outcome.

RESULTS

Thirty out of 51 patients were males. The median age was 63 years (range 34-81). The median follow-up was 17 months. Thirty-six patients had node-positive disease. The majority of patients (n = 43) had T2 and T3 disease. Vascular and lymphatic invasions were present in 57 and 77% of tumors, respectively. VEGF and HIF-1alpha were positive in 65 and 71% of tumors. The median CD34 staining score was 19 (3-68). VEGF, HIF-1alpha and CD34 expressions were more frequent in tumors without serosal invasion (p = 0.01, p = 0.01 and p = 0.003, respectively). CD34 expression was significantly more frequent in tumors with VEGF and HIF-1alpha expression (p = 0.00, p = 0.00). HIF-1alpha expression was more frequent in tumors with VEGF expression (p = 0.00). The 5-year overall survival was 45%. VEGF, HIF-1alpha, CD34 expressions and other pathological characteristics were found to have no impact on survival.

CONCLUSION

VEGF, HIF-1alpha and CD34 expressions were more common in tumors without serosal invasion. As a future perspective, biological agents targeting VEGF and HIF-1alpha might be more effective at earlier stages of gastric cancer.

Expression of cyclooxygenase-2 and vascular endothelial growth factor-C correlates with lymphangiogenesis and lymphatic invasion in human gastric cancer

BACKGROUND

Recent observations have suggested that overexpression of cyclooxygenase-2 (COX-2) promotes tumor lymphangiogenesis through an upregulation of vascular endothelial growth factor-C (VEGF-C) expression. It is unclear whether this mechanism also acts in gastric cancer. The aim of this study was to determine the relationship between COX-2 and VEGF-C expression in human gastric cancer, as well as to correlate with lymph node involvement, prognosis, and other clinicopathologic parameters.

METHODS

Sixty-eight primary gastric cancers were immunohistochemically examined for COX-2, VEGF-C, vascular endothelial growth factor receptor-3 (VEGFR-3, also known as Flt-4), and CD34 expressions. Assessment of Flt-4-positive vessel density (FVD) and microvessel density (MVD) was performed. Then we analyzed their relationships and correlations with clinicopathologic findings and patients' survival time.

RESULTS

The positivity rate of COX-2 and VEGF-C in the primary tumor was 67.7 and 54.4 percent, respectively. A significant correlation was found between the expression of VEGF-C and COX-2, and both were also correlated to MVD, FVD, lymphatic invasion, and TNM stage (p<0.05). COX-2 immunoreactivity was also associated with lymph node metastasis and serosa invasion. Increased MVD was significantly associated with lymph node metastasis and TNM stage. Both COX-2 and VEGF-C expression significantly correlated with poorer prognosis.

CONCLUSIONS

Our data suggest that the expression of COX-2 correlates with VEGF-C expression and both of them correlate with the presence of lymphatic invasion and prognosis in gastric cancer. COX-2-mediated VEGF-C overexpression might promote lymphatic invasion via lymphangiogenesis pathway in patients with gastric cancer.

VEGF-C and VEGF-A synergistically enhance lymph node metastasis of gastric cancer

PURPOSE

Vascular endothelial growth factor C (VEGF-C) is the most important molecule in lymphangiogenesis and its relationship with lymph node metastasis has attracted considerable interest. We investigated the relationship of VEGF-C or VEGF-A with clinicopathological factors in gastric cancer patients.

METHODS

Eighty gastric cancer patients who underwent gastric resection were analyzed immunohistochemically for expression of VEGF-C and VEGF-A protein.

RESULTS

Positive immunoreactivity of VEGF-C and VEGF-A was observed in 75 (93.8%) and 41 (51.3%) patients, respectively. VEGF-A expression was significantly correlated with tumor differentiation (p=0.0017) and vascular invasion (p=0.0004). And positive relationship of VEGF-C expression was only demonstrated with tumor differentiation (p=0.0168). Interestingly, however, the frequency of lymph node metastasis was significantly higher in the patients with expression of both VEGF-C and VEGF-A (strong positive expression, p=0.036). Furthermore, the expression of both was also significantly correlated with depth of tumor invasion, tumor differentiation, lymphatic invasion, and vascular invasion.

CONCLUSION

The present results suggest that strong expression of VEGF-A in addition to VEGF-C expression is essential in lymph node metastasis, presumably because enhanced metastatic potential including lymphangiogenesis induced by both VEGF-A and VEGF-C is vital in lymph node metastasis of gastric cancer.

Expression of vascular endothelial growth factor (VEGF)-C and -D in gastric carcinoma

BACKGROUND

Both vascular endothelial growth factor (VEGF)-C and (VEGF)-D are ligands of VEGF receptor (VEGFR)-3 (Flt-4) and VEGFR-2 (KDR/FLK-1) and are supposed to participate in lymphangiogenesis. The purpose of this study was to clarify the clinical significance of the expression of these factors and to evaluate their relationship with prognosis in patients with gastric carcinoma.

METHODS

Fifty pairs of normal mucosa and cancer specimens were obtained from patients who had undergone gastrectomy for primary gastric carcinoma and subjected to reverse transcriptase-polymerase chain reaction for VEGF-C, VEGF-D, and VEGFR-3.

RESULTS

Both VEGF-C and VEGF-D mRNA expression significantly correlated with lymphatic invasion (P < 0.05). Although VEGF-C and -D were concomitantly expressed in most cases, only VEGF-C expression was related to lymph node metastasis. VEGFR-3 expression was associated both with VEGF-C and VEGF-D expression, but not with lymph node metastasis. Tumors expressing these mRNAs tended to correlate with poorer prognosis, but the relationships were not statistically significant.

CONCLUSION

Our study suggests that both VEGF-C and VEGF-D are involved in lymphatic spreading of gastric cancer cells, which is clinically useful for the evaluation of lymphatic invasion in patients with gastric carcinoma.

Occult breast cancer presenting as axillary metastases

We report the case of a 52-year-old woman with occult breast cancer who presented with a hard metastatic nodule in the left axilla. Although histology identified a metastatic adenocarcinoma in the lymph nodes, numerous tests failed to detect the primary tumor. Immunohistochemistry showed that the resected lymph node was positive for both estrogen and progesterone receptors, suggesting the breast as the site of the primary tumor. Left modified radical mastectomy was performed. Pathology revealed an invasive ductal carcinoma (1.5x1 mm in size) with extensive lymphatic involvement, which strongly expressed both vascular endothelial growth factor-C (VEGF-C) and VEGF-D.

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Prognostic significance of vascular endothelial growth factor D in gastric carcinoma

The angiogenic factor called vascular endothelial growth factor (VEGF)-D is a ligand for VEGF receptor-2 (VEGFR-2/KDR) and receptor-3 (VEGFR-3/Flt-4). It is implicated in the development of lymphatic vessels and promotion of lymphatic metastasis. The purpose of this study was to investigate the prognostic significance of VEGF-D expression in patients with gastric carcinoma. We assessed the expression of VEGF-D in gastric carcinoma by immunohistochemistry on 143 consecutive patients' stored sections and evaluated the lymphatic vessel count (LVC) in tumors using the novel selective lymphatic endothelium marker D2-40. VEGF-D expression was observed in 55 (39%) tumor sections. The expression of VEGF-D correlated significantly with tumor size, T of the TNM classification, lymphatic and venous system invasion, LVC, lymph node metastasis, M of TNM, and pTNM stage. Multivariate analysis indicated that VEGF-D expression was an independent prognostic factor for both relapse-free survival (RFS) and overall survival (OS). Our data indicate the involvement of VEGF-D in tumor progression via lymphoangiogenic pathways. Practically, VEGF-D expression can be useful for predicting RFS and OS in patients with gastric carcinoma.

Tumor-induced lymphangiogenesis: a target for cancer therapy?

Recent advances in understanding the biology of lymphangiogenesis, the new growth of lymphatic vessels, have cast new light on the molecular basis of metastasis to regional lymph nodes. The receptor tyrosine kinase VEGFR-3 is virtually exclusively expressed on lymphatic but not blood endothelium in the adult, and activation of VEGFR-3 by its ligands VEGF-C and VEGF-D is sufficient to induce lymphangiogenesis. Correlative studies with human tumors and functional studies using animal tumor models show that increased levels of VEGF-C or VEGF-D in tumors lead to enhanced numbers of lymphatic vessels in the vicinity of tumors, which in turn promotes metastasis to regional lymph nodes by providing a greater number of entry sites into the lymphatic system for invading tumor cells. These findings have prompted studies to investigate whether inhibitors of VEGFR-3 activation might represent novel therapeutic agents for the suppression of metastasis. However, a number of points regarding the therapeutic potential of anti-lymphangiogenic treatments in the context of cancer remain to be addressed. The spectrum and relative importance of molecules that induce lymphangiogenesis and the regulation of their expression during tumor progression, the reversibility of tumor-induced lymphangiogenesis, and possible side-effects of anti-lymphangiogenesis-based therapies all need to be investigated. Most importantly, the extent to which lymph node metastases contribute to the formation of metastases in other organs remains to be elucidated. These aspects are the focus of this review, and their investigation should serve as a roadmap to possible translational application.

Overexpression of cyclooxygenase-2 in gastric cancer correlates with the high abundance of vascular endothelial growth factor-C and lymphatic metastasis

Cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF)-C are closely related with the development and metastasis of tumors. The gene expression of COX-2 and VEGF-C in gastric cancer and the correlation between them were investigated; 64 paraffin-embedded gastric cancer samples and 22 flesh gastric cancer samples were tested by using immunohistochemistry and the reverse transcription polymerase chain reaction (RT-PCR) technology, respectively. The mean expressive density of COX-2 and VEGF-C mRNA in gastric cancer, with beta-actin coamplified as an internal standard, were both significantly higher than those in non-cancerous gastric mucosa (1.363 +/- 0.351 vs 0.763 +/- 0.304, 0.972 +/- 0.331 vs 0.314 +/- 0.215, p < 0.001). The positive rates of COX-2 and VEGF-C in 64 gastric cancer samples were 72% and 64% respectively. Their expression in the lymph-node metastasis groups were higher than that of the non-lymph-node metastasis groups (p < 0.05). Moreover, there was a close correlation between COX-2 and VEGF-C expression levels (p < 0.05). The study indicates gastric tumor tissues that produce COX-2 and VEGF-C may have a higher lymphatic invasion and metastatic potential. COX-2 may participate in VEGF-C lymphangiogenic pathway and the high expression of them may play an important role in the lymphatic proliferation and spread in gastric cancer.

Overexpression of cyclooxygenase-2 in gastric cancer correlates with the high abundance of vascular endothelial growth factor-C and lymphatic metastasis

Cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF)-C are closely related with the development and metastasis of tumors. The gene expression of COX-2 and VEGF-C in gastric cancer and the correlation between them were investigated; 64 paraffin-embedded gastric cancer samples and 22 flesh gastric cancer samples were tested by using immunohistochemistry and the reverse transcription polymerase chain reaction (RT-PCR) technology, respectively. The mean expressive density of COX-2 and VEGF-C mRNA in gastric cancer, with beta-actin coamplified as an internal standard, were both significantly higher than those in non-cancerous gastric mucosa (1.363 +/- 0.351 vs 0.763 +/- 0.304, 0.972 +/- 0.331 vs 0.314 +/- 0.215, p < 0.001). The positive rates of COX-2 and VEGF-C in 64 gastric cancer samples were 72% and 64% respectively. Their expression in the lymph-node metastasis groups were higher than that of the non-lymph-node metastasis groups (p < 0.05). Moreover, there was a close correlation between COX-2 and VEGF-C expression levels (p < 0.05). The study indicates gastric tumor tissues that produce COX-2 and VEGF-C may have a higher lymphatic invasion and metastatic potential. COX-2 may participate in VEGF-C lymphangiogenic pathway and the high expression of them may play an important role in the lymphatic proliferation and spread in gastric cancer.

Role of VEGF-C and VEGF-D in lymphangiogenesis in gastric cancer

BACKGROUND

The molecular mechanisms of lymphangiogenesis induced by vascular endothelial growth factor (VEGF)-C and VEGF-D in gastric cancer were studied.

METHODS

VEGF-C and VEGF-D gene expression vectors were transfected into the gastric cancer cell line KKLS, which did not originally express VEGF-C and VEGF-D, and stable transfectants (KKLS/VEGF-C and KKLS/VEGF-D) were established. The cell lines were inoculated into the subserosal layer of the stomach and subcutaneous tissue of nude mice.

RESULTS

VEGF-C and VEGF-D expression in KKLS/VEGF-C and KKLS/VEGF-D cells was found by reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. Expression of mouse VEGF receptor (VEGFR)-2 and mouse VEGFR-3 mRNA was detected in the KKLS/VEGF-C and KKLS/VEGF-D gastric tumors. Newly formed lymphatic vessels were detected not only in the periphery but also in the center of the tumors. The intratumor lymphatic vessels connected with the preexisting lymphatic vessels in the muscularis mucosa. The average numbers of lymphatic vessels in KKLS/VEGF-C (52.0 +/- 9.5) and KKLS/VEGF-D (16.4 +/- 0.6) gastric tumors were significantly higher than that in the KKLS/control vector tumors (4.0 +/- 1.4).

CONCLUSION

VEGF-C and VEGF-D may induce neoformation of lymphatic vessels in experimental gastric tumors by the induction of VEGFR-3 expression.

Anti-angiogenic treatment of gastrointestinal malignancies

The scientific rationale to block angiogenesis as a treatment strategy for human cancer has been developed over the last 30 years, but is only now entering the clinical arena. Preclinical studies have demonstrated the importance of the vascular endothelial growth factor (VEGF) pathways in both physiologic and pathologic angiogenesis, and have led to the development of approaches to block its role in tumor angiogenesis. Bevacizumab is an antibody to VEGF and has been shown to prolong survival when given with chemotherapy in the treatment of metastatic colorectal cancer (CRC). Although this is the first anti-angiogenic treatment to be approved for the treatment of human epithelial malignancy, a number of other approaches currently are in development. Soluble chimeric receptors to sequester serum VEGF and monoclonal antibodies against VEGF receptors have both shown considerable promise in the laboratory and are being brought into clinical investigation. A number of small-molecule tyrosine kinase inhibitors that have activity against VEGF receptors also are in clinical trials. Although these novel treatments are being pioneered in CRC, anti-angiogenic approaches also are being tested in the treatment of other gastrointestinal malignancies. Anti-VEGF therapy has shown promise in such traditionally resistant tumors as pancreatic cancer and hepatocellular carcinoma. This review will examine the preclinical foundation and then focus on the clinical studies of anti-VEGF therapy in gastrointestinal cancers.

Expression of vascular endothelial growth factor (VEGF)-C and VEGF-D in early gastric carcinoma: correlation with clinicopathological parameters

In this study, we investigated whether expression of vascular endothelial growth factor (VEGF)-C and/or VEGF-D correlates with clinicopathological features of human gastric carcinoma. We immunohistochemically examined the expression of VEGF-C and VEGF-D in 140 archival surgical specimens of submucosally invasive gastric carcinoma. Of these specimens, 32 (22.9%) and 12 (8.6%) showed intense VEGF-C and VEGF-D immunoreactivity in cancer cells, respectively. VEGF-C immunoreactivity was associated with histological type, lymphatic invasion, lymph node metastasis, and microvessel density. No association was identified between VEGF-D immunoreactivity and clinicopathological variables. These results suggest that VEGF-C is a dominant regulator of lymphangiogenesis in early-stage human gastric carcinoma.

Vascular Endothelial Growth Factor-D and Its Receptor VEGFR-3: Two Novel Independent Prognostic Markers in Gastric Adenocarcinoma

Purpose

Vascular endothelial growth factor (VEGF)-D and its homolog VEGF-C influence lymphangiogenesis through activation of VEGF receptor 3 (VEGFR-3), and have been implicated in lymphatic tumor spread. Nodal dissemination of gastric adenocarcinomas critically determines clinical outcome and therapeutic options of affected patients. Therefore, we analyzed expression and prognostic significance of VEGF-D along with VEGF-C, and VEGFR-3 in gastric adenocarcinomas.

Materials and Methods

VEGF-C, VEGF-D, and VEGFR-3 were analyzed in 91 R0-resected primary gastric adenocarcinomas, corresponding noncancerous gastric mucosa, and lymph node metastases employing immunohistochemistry and/or in situ hybridization. Blood and lymph vessel densities were assessed after staining with CD31 and LYVE-1–specific antibodies.

Results

VEGF-D and VEGF-C were detected in 67.0% and 50.5% of gastric cancers, respectively. Healthy gastric mucosa was negative for VEGF-C and in 12.5% positive for VEGF-D. Presence of VEGF-D (P = .005) or VEGF-C (P = .006) was correlated with lymphatic metastases and decreased survival (VEGF-D, P < .05; VEGF-C, P < .05). VEGFR-3 was correlated with reduced carcinoma-specific survival (P < .05), and Cox multivariate regression analysis qualified VEGF-D and VEGFR-3, but not VEGF-C, as independent prognostic parameters. In lymph node–positive gastric cancers, presence of VEGF-D/VEGFR-3 was associated with poor survival, whereas absence of VEGF-D/VEGFR-3 defined a subgroup of patients with clearly favorable prognosis.

Conclusion

VEGF-D and VEGFR-3 are novel independent prognostic marker molecules aiding to identify patients with poor prognosis after curative resection of gastric adenocarcinomas. Combined analysis of the VEGF-C/VEGF-D/VEGFR-3 system can be useful to identify patients with unfavorable clinical outcome and thereby may help to refine therapeutic decisions in gastric cancer.

Expression and correlation of CD44v6, vascular endothelial growth factor, matrix metalloproteinase-2, and matrix metalloproteinase-9 in Krukenberg tumor

AIM: To explore the expression and correlation of CD44v6, vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-2 and matrix metalloproteinase (MMP)-9 in Krukenberg and primary epithelial ovarian carcinoma.

METHODS: The expressions of CD44v6, VEGF, MMP-2 and MMP-9 were detected by immunohistochemical method in 20 cases of normal ovarian tissues, 38 cases of Krukenberg tumor and 45 cases of primary epithelial ovarian carcinoma.

RESULTS: The expression of CD44v6 (primary epithelial ovarian carcinoma tissue vs normal ovarian tissue: χ² = 4.516, P = 0.034; Krukenberg tumor tissue vs normal ovarian tissue: χ² = 19.537, P = 0.001) and VEGF (primary epithelial ovarian carcinoma tissue vs normal ovarian tissue: P = 0.026; Krukenberg tumor tissue vs normal ovarian tissue: χ² = 22.895, P = 0.001) was significantly higher in primary epithelial ovarian carcinoma tissue and Krukenberg tumor tissue than in normal ovarian tissue. The positive expression rate of MMP-2 and MMP-9 was 0% in the normal ovarian tissue. The positive expression rate of CD44v6 (χ² = 10.398, P = 0.001), VEGF (χ² = 13.149, P = 0.001), MMP-2 (χ² = 33.668, P = 0.001) and MMP-9 (χ² = 38.839, P = 0.001) was remarkably higher in Krukenberg tumor than in primary epithelial ovarian carcinoma. The correlation of CD44v6, VEGF, MMP-2, and MMP-9 was observed in primary epithelial ovarian carcinoma and Krukenberg tumor.

CONCLUSION: CD44v6, VEGF, MMP-2, and MMP-9 are involved in ovarian carcinoma, gastric cancer and Krukenberg tumor. Detection of CD44v6, VEGF, MMP-2 and MMP-9 may contribute to the diagnosis of ovarian carcinoma, gastric cancer, and Krukenberg tumor.

Effect of Weikangning on gastric cancer cell growth and expression of vascular endothelial growth factor and its receptors KDR and Flt-1

AIM: To observe the effect of Chinese traditional herbal decoction Weikang-ning (WKN) on cell growth and expression of VEGF and its receptors KDR and Flt-1 in gastric cancer cell line MGC-803.

METHODS: A total of 120 male Wistar rats were divided into control group, high dose, medium dose and low dose groups fed with natural saline, 20, 10, and 5 g/kg of WKN, respectively. The experimental animals were finally killed for the preparation of drug-containing serum. The gastric cancer cell MGC-803 was cultured with the drug-containing serum drawn from the rats in different groups. We observed the growth condition of the cancer cells with light microscope and flow cytometer. The expression of mRNA of VEGF and its receptors KDR and Flt-1 was detected with RT-PCR.

RESULTS: The proportion of cells in G₀-G₁ phase was (65.40±0.41)%, (56.92±0.62)%, (55.89±0.69)% in high, medium and low dose groups respectively vs (41.35±0.55)% in control group (P<0.01), while the cells in G₂-S and S phases were (11.62±0.62)% and (22.99±0.69)%, (17.08±0.80)% and (26.00±0.71)%, (19.37±0.57)% and (24.74±0.64)% in high, medium and low dose groups, respectively, vs (23.65±0.56)% and (35.00±0.60)% in control group (P<0.01). The expression of mRNA of VEGF and its receptors was significantly decreased, the area of electrophoresis bands (AREA), the absorptivity of mean optical density (A) and the product of AREA and A were significantly lower in WKN-administered groups than that in control group (P<0.01).

CONCLUSION: The decoction of WKN suppresses the growth of gastric cancer cell MGC-803 and decreases the expression of mRNA of both VEGF and its receptors KDR and Flt-1.

Lymphangiogenic growth factors as markers of tumor metastasis

Understanding the complex process of tumor metastasis is a problem which has challenged both clinician and scientist for well over 100 years. Defining molecular markers which reflect the metastatic potential of a tumor has also proved elusive. Recently, members of the vascular endothelial growth factor (VEGF) family of glycoproteins have been demonstrated to be potent mediators of both blood vessel and lymphatic vessel formation in the context of tumor biology. Experimental studies in animal models combined with extensive clinicopathological data provide a compelling case indicating that members of the VEGF family play a key role in the formation of metastases in a broad range of solid tumors. The question of whether VEGF signaling pathways can now serve as therapeutic targets alone, or in combination with other forms of anti-cancer agents, needs to be addressed.

Expression of vascular endothelial growth factor (VEGF)-C in preoperative biopsy specimens and metastatic foci of regional lymph nodes in submucosal gastric carcinoma

BACKGROUND: Vascular endothelial growth factor (VEGF)-C is implicated in lymphangiogenesis, however the exact role of VEGF-C in promoting lymphatic spread of cancer cells remains largely unknown. METHODS: The expression of VEGF-C was immunohistochemically determined in 97 endoscopic biopsy specimens from 46 patients with submucosal gastric carcinoma (SGC). Nodal metastases including micrometastasis and isolated tumor cells (ITC) were evaluated by immunohistochemical staining for cytokeratin in 1650 lymph nodes, and tumor cells in these metastatic nodes were also examined for VEGF-C expression. RESULTS: In biopsy samples, VEGF-C was positively detected in 21 (47%) patients. Metastases were identified in 46 (2.8%) nodes from 15 (33%) patients. Metastases were detected in 39 nodes by hematoxylin-eosin (H&E) staining and in additional 7 nodes as ITC by immunohistochemical staining. The rate of lymph node metastases was significantly correlated with VEGF-C expression in biopsy samples (p < 0.05). The positive and negative predictive values of VEGF-C in biopsy specimens for nodal metastasis were 44 %(10/21) and 80% (20/25), respectively. Among the 46 metastatic nodes, tumor cells in 29 (63%) nodes positive patients expressed VEGF-C, whereas those in 17 (37%) nodes did not. VEGF-C expression was high in macronodular foci in medullary areas, whereas more than half of ITC or micrometastasis located in peripheral sinus lacked the expression of VEGF-C. CONCLUSIONS: Despite the significant correlation, immunodetcetion of VEGF-C in endoscopic biopsy specimens could not accurately predict the nodal status, and thus cannot be applied for the decision of the treatment for SGC. VEGF-C may not be essential for lymphatic transport, but rather important to develop the macronodular lesion in metastatic nodes.

Expression of tumor metastasis-related gene protein in the same syndromic classification of gastric carcinoma on traditional Chinese medicine

AIM: To explore the entity of gastric carcinoma under the same syndromic classification based on traditional Chinese medicine from the angle of gene protein expression.

METHODS: Patients with gastric carcinoma were collected and then classified before operation according to dialectic criterion of traditional Chinese medicine. Samples of gastric carcinoma from all the patient were collected after operation. EnVision two step immuhistochemical method was used to observe the expession of E-cadherin, C-erbB-2, P53, nm23, ICAM-1, VEGF, KDR, MMP-2, TIMP-2 in the cancerous samples.

RESULTS: The preceding 9 gene proteins were differently expressed in each type. There was significant difference (P = 0.0 001 < 0.01) in the expression of the 9 gene proteins between different syndromic types. Several genes had different expression in the same syndromic type. The rates of VEGF, E-cad, nm23 expression were higher (94%, 90% and 92% respectively) than other proteins. E-cad expression in the stagnation of phlegm-damp type is the highest expression (average rank = 63.09). E-cad expression was lower in the types of the stasis and endogenous toxics and the discordance of liver-stomach.

CONCLUSION: Metastasis of gastric carcinoma in the types of the stasis and endogenous toxics and the discordance of liver-stomach may relate to the loss of E-cadherin expression. However, both cancer gene and anti-oncogene are expressed at a high level in the two types.

Pathobiological significance of vascular endothelial growth factor and Maspin expressions in human gastric carcinoma

AIM: To investigate the correlation between expression of vascular endothelial growth factor (VEGF) and cell differentiation, invasion, metastasis and Maspin expression in gastric carcinoma.

METHODS: Formalin-fixed paraffin-embedded tissue specimens from 73 cases of gastric carcinoma were studied with SP immunohistochemistry, using anti-VEGF monoclonal antibody, and thirty-nine of them were studied using anti-Maspin monoclonal antibody. VEGF expression was compared with the clinical stage, lymph node metastasis, and Borrmann's and WHO's classification of gastric carcinoma.

RESULTS: The positive rate of VEGF expression was significantly higher in adjacent non-carcinoma epithelia (ANCE) than in non-metaplastic, non-carcinoma gastric epithelia (NMNCE), which were at least 4 cm distant from the primary tumor (P = 0.000, χ² = 73.03). The positive rate of VEGF expression was significantly higher in advanced gastric carcinoma (AGC) than in early gastric carcinoma (EGC) (P = 0.032, χ² = 4.62). The positive rate of VEGF expression in gastric carcinomas with lymph node metastases was significantly higher than that in those without metastasis (P = 0.006, χ² = 7.47). Maspin was weakly expressed in 16 out of 39 cases of NMNCE, and the positive immunoreaction was limited to gland cells of the stomach body. There was no significant correlation between the expression of VEGF and histological or gross classifications, and correlation between the expressions of VEGF and Maspin in gastric carcinoma (P = 0.648, χ² = 0.21).

CONCLUSION: Expression of VEGF is significantly correlated to the malignant biological behaviors of gastric carcinoma, but there is no significant correlation between the expression of VEGF and Maspin.

Enhancement of pleural dissemination and lymph node metastasis of intrathoracic lung cancer cells by vascular endothelial growth factors (VEGFs)

The expression of vascular endothelial growth factors (VEGFs) in tumors including lung cancer is considered to be associated with tumor development via capillary and lymph vessel neogenesis. Dissemination of the tumor cells to the pleura or regional lymph nodes is a critical poor prognostic factor for lung cancer patients. To investigate how VEGFs expressed in the intrathoracic infiltrating lung cancer cells participate in disease progression, we established stably VEGF-A-, VEGF-C-, VEGF-D-, VEGF-A and VEGF-C-, and VEGF-A and VEGF-D-expressing large cell lung cancer clones (TKB5/VEGF-A, TKB5/VEGF-C, TKB5/VEGF-D, TKB5/VEGF-A/C, and TKB5/VEGF-A/D), orthotopically inoculated these into the right thoracic cavity (i.t.) of nude mice, and evaluated the subsequent development of lung lesion, pleural effusion, pleural dissemination, and lymph node metastasis. While there were no significant differences either in culture or in subcutaneous tumor cell growth between the empty vector-transfected group (TKB5/empty) and each transfectant, the i.t. model demonstrated significantly different biological properties between the transfectants. TKB5/empty-inoculated mice frequently developed a large tumor on the pleura without pleural effusion, dissemination, or lymph node (LN) metastasis. In contrast, VEGF-A promoted a bloody pleural effusion (6/14), and VEGF-A and VEGF-D frequently generated pleural dissemination (11/14 and 9/11, respectively). Although both VEGF-C and VEGF-D generated LN metastasis (6/10 and 8/11, respectively), the locations of the metastasized LNs were quite different. TKB5/VEGF-C metastasized on the same side of axillary LNs as i.t. (right axillary LNs), whereas TKB5/VEGF-D metastasized to the mediastinal and left axillary and/or cervical LNs. Since the TKB5/VEGF-A/C or TKB5/VEGF-A/D co-transfectants revealed overlapping tumor progression patterns of VEGF-A and VEGF-C or VEGF-D, the metastatic LNs had abundant new capillaries and were larger than those of TKB5/VEGF-C or TKB5/VEGF-D-inoculated mice. Our results clearly demonstrate that VEGF-A secreted from intrathoracic lung cancer cells plays important roles in producing pleural effusion, dissemination, and capillary neogenesis, that VEGF-C is involved in LN metastasis, and VEGF-D in pleural dissemination and LN metastasis. It is most likely, however, that the mechanisms by which VEGF-C promotes LN metastasis are different from those of VEGF-D. The regulation of the expression of VEGFs in intrathoracic lung cancer cells might be a useful therapeutic approach to inhibiting tumor development and improving patient prognosis.

Role of lymphangiogenic factors in tumor metastasis

Nearly four centuries after the discovery of lymphatic vessels, the molecular mechanisms underlying their development are beginning to be elucidated. Vascular endothelial growth factor C (VEGF-C) and VEGF-D, via signaling through VEGFR-3, appear to be essential for lymphatic vessel growth. Observations from clinicopathological studies have suggested that lymphatic vessels serve as the primary route for the metastatic spread of tumor cells to regional lymph nodes. Recent studies in animal models have provided convincing evidence that tumor lymphangiogenesis facilitates lymphatic metastasis. However, it is not clear how tumor-associated lymphangiogenesis is regulated, and little is known about how tumor cells escape from the primary tumor and gain entry into the lymphatics. This review examines some of these issues and provides a brief summary of the recent developments in this field of research.

Effect of Chinese medicine Weikangning on expression of VEGF and its receptors Flt and KDR in gastric carcinoma cells

AIM: To study effect of traditional Chinese medicine Weikangning (WKN) on the expression of VEGF and its receptors Flt and KDR in gastric carcinoma cells.

METHODS: We used different dosage of WKN on rats to prepare serum containing WKN.The gastric carcinoma cells were cultured in the RPMI1640 media with serum containing WKN for 48 h. The expression of VEGF, Flt-1 and KDR was determined by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry in gastric cancer cell lines respectively.

RESULTS: All gastric cancer cell lines analyzed expressed VEGF Flt-1 and KDR. But the expression of fVEGF (186.82±0.22, 195.35±0.45, 172.62±0.52), Flt-1 (198.44±0.44, 188.66±0.46, 197.01±0.91) in cells cultured in serum containing WKN decreased in a dose-dependent manner as compared with control (VEGF162. 78±0.58, Flt: 172.65±0.65)(P < 0.05).

CONCLUSION: VEGF and its receptors KDR and Flt-1 are expressed widely in gastric carcinoma cells and WKN can inhibit their expression.

Expression of vascular endothelial growth factor C and chemokine receptor CCR7 in gastric carcinoma and their values in predicting lymph node metastasis

AIM: To study the expression of vascular endothelial growth factor C (VEGF-C) and chemokine receptor CCR7 in gastric carcinoma and to investigate their associations with lymph node metastasis of gastric carcinoma and their values in predicting lymph node metastasis.

METHODS: The expression of VEGF-C and CCR7 in gastric carcinoma tissues obtained from 118 patients who underwent curative gastrectomy was examined by immunohistochemistry. Among these patients, 39 patients underwent multi-slice spiral CT (MSCT) examination.

RESULTS: VEGF-C and CCR7 were positively expressed in 52.5 and 53.4% of patients. VEGF-C expression was more frequently found in tumors with lymph node metastasis than those without it (P < 0.001). VEGF-C expression was also closely related to lymphatic invasion (P < 0.001), vascular invasion (P < 0.01), and TNM stage (P < 0.001). However, there was no significant correlation between VEGF-C expression and age at surgery, gender, tumor size, tumor location, Lauren classification, and depth of invasion. CCR7 expression was significantly higher in patients with lymph node metastasis compared with those without lymph node metastasis (P < 0.001) and was also associated with tumor size (P < 0.01), depth of invasion (P < 0.001), lymphatic invasion (P < 0.001), and TNM stage (P < 0.001). However, the presence of CCR7 had no correlation to age at surgery, gender, tumor location, Lauren classification, and vascular invasion. Among the 39 patients who underwent MSCT examination, only CCR7 expression was related to lymph node metastasis determined by MSCT (P < 0.05). In the current retrospective study, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of VEGF-C and CCR7 expression in the diagnosis of lymph node metastasis for patients with gastric carcinoma were 73.8%, 70.2%, 72.6%, 71.4% and 72.0%, and 82.0%, 77.2%, 79.4%, 80.0% and 79.7%, respectively. After subdivision according to the combination of VEGF-C and CCR7 expression, receiver operating characteristic (ROC) analysis showed that the accuracy of the combined examination of VEGF-C and CCR7 expression in predicting lymph node metastasis was relatively high (area under ROC curve [Az] = 0.83).

CONCLUSION: The expression of VEGF-C and CCR7 is related to lymph node metastasis of gastric carcinoma and both of them may become new targets for the treatment of gastric carcinoma. Furthermore, the combined examination of VEGF-C and CCR7 expression in endoscopic biopsy specimens may be useful in predicting lymph node metastasis of gastric carcinoma and deciding the extent of surgical lymph node resection.

Expression and significance of VEGF-C and FLT-4 in gastric cancer

AIM: To investigate the expression of pathological factors of VEGF-C and its receptor FLT-4 in primary gastric cancer and adjacent normal tissues.

METHODS: The expression of VEGF-C and FLT-4 was studied in 80 primary gastric cancers and adjacent normal tissues from the same patients by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and immumohistochemistry.

RESULTS: Both primary gastric cancer and adjacent normal tissue could express VEGF-C and FLT-4, and FLT-4 expression was also detected in endothelial cells of stromal blood vessels and lymphatic vessels. There was a significant difference in expression of VEGF-C between primary tumor and adjacent normal tissue samples (P = 0.01), and a statistical correlation between VEGF-C and FLT-4 expression in tumors (P = 0.00886). With regard to VEGF-C expression, there was a significant difference between moderate-poor differential type and high differential type (P = 0.032), and a significant difference between positive and negative lymph node metastases (P = 0.024). However, there was no significant difference between positive and negative serosal invasions (P = 0.219).

CONCLUSION: VEGF-C and its receptor FLT-4 play a role in the development of gastric cancer, and the tumors with expression of VEGF-C and FLT-4 are more likely to have lymph node metastasis.

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