The expression of vascular endothelial growth factor C and its receptors in non-small cell lung cancer

Vascular endothelial growth factor receptors VEGFR-2 and VEGFR-3 are localized primarily to the vasculature in human primary solid cancers

PURPOSE

Vascular endothelial growth factor (VEGF) signaling is key to tumor angiogenesis and is an important target in the development of anticancer drugs. However, VEGF receptor (VEGFR) expression in human cancers, particularly the relative expression of VEGFR-2 and VEGFR-3 in tumor vasculature versus tumor cells, is poorly defined.

EXPERIMENTAL DESIGN

VEGFR-2- and VEGFR-3-specific antibodies were identified and used in the immunohistochemical analysis of human primary cancers and normal tissue. The relative vascular localization of both receptors in colorectal and breast cancers was determined by coimmunofluorescence with vascular markers.

RESULTS

VEGFR-2 and VEGFR-3 were expressed on vascular endothelium but not on malignant cells in 13 common human solid tumor types (n > 400, bladder, breast, colorectal, head and neck, liver, lung, skin, ovarian, pancreatic, prostate, renal, stomach, and thyroid). The signal intensity of both receptors was significantly greater in vessels associated with malignant colorectal, lung, and breast than adjacent nontumor tissue. In colorectal cancers, VEGFR-2 was expressed on both intratumoral blood and lymphatic vessels, whereas VEGFR-3 was found predominantly on lymphatic vessels. In breast cancers, both receptors were localized to and upregulated on blood vessels.

CONCLUSIONS

VEGFR-2 and VEGFR-3 are primarily localized to, and significantly upregulated on, tumor vasculature (blood and/or lymphatic) supporting the majority of solid cancers. The primary clinical mechanism of action of VEGF signaling inhibitors is likely to be through the targeting of tumor vessels rather than tumor cells. The upregulation of VEGFR-3 on tumor blood vessels indicates a potential additional antiangiogenic effect for dual VEGFR-2/VEGFR-3-targeted therapy.

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.

Pancreatic stellate cells increase the invasion of human pancreatic cancer cells through the stromal cell-derived factor-1/CXCR4 axis

AIM

Both pancreatic stellate cells (PSCs) and the stromal cell-derived factor-1(SDF-1)/CXCR4 receptor ligand system have important roles in pancreatic cancer progression. This study set out to detect if PSCs express SDF-1 and promote the invasion of pancreatic cancer through the SDF-1/CXCR4 receptor ligand axis.

METHODS

RT-PCR was performed to detect the expression of SDF-1 and CXCR4 in PSCs, pancreatic cancer lines and cancer tissue samples. ELISA was used to investigate the concentration of SDF-1 in PSC supernatants. An MTT assay was applied to detect the proliferation of pancreatic cancer cells. A transwell chamber migration assay was employed to detect the migration of AsPC-1 cells. An in vitro invasion assay was used to detect the invasion of AsPC-1 cells.

RESULTS

CXCR4 expression was detected in PSCs; AsPC-1, SW1990 and BxPC-3 cancer cells; and cancer tissues. SDF-1 was detected in PSCs and cancer tissues, but not in AsPC-1, SW1990 and BxPC-3 cells. SDF-1alpha protein was found in PSC supernatants. PSC-conditioned media can promote the proliferation, migration and invasion of pancreatic cancer cells. SDF-1 neutralizing antibody or AMD3100 can significantly inhibit these promotive and IAP.

Association between lymphangiogenesis-/micrometastasis- and adhesion-related molecules in resected stage I NSCLC

BACKGROUND

The purpose of this study was to clarify the role and clinical significance of lymphangiogenesis/micrometastases and adhesion molecules in resected stage I non-small cell lung cancer (NSCLC).

METHODS

Immunohistochemical (IHC) staining was used to analyze the protein expression of vascular endothelial growth factor-C (VEGF-C), VEGF, E-cadherin, alpha-catenin, beta-catenin, and gamma-catenin in paraffin-embedded tumor samples from 117 well-characterized stage I NSCLC patients and to compare the protein expression, clinical variables and survival outcome. As a micrometastatic parameter in lymph nodes (LNs), cytokeratin (CK) staining was performed.

RESULTS

The positive expression of VEGF-C and VEGF were detected in 54 (48.7%) and 86 (73.5%), respectively. We identified micrometastatic tumor cells in pathological N0 LNs in 34 (29.1%) of 117 patients. E-cadherin, alpha-catenin, beta-catenin, and gamma-catenin were identified in 70 (59.8%), 41 (35.0%), 83 (70.9%), and 61 (52.1%) specimens, respectively. The VEGF-C expression was found more frequently in squamous cell carcinoma (SQ) and in the tumors with negative expression of beta-catenin than counter features. The VEGF expression was found more frequently in the tumors with a negative expression of E-cadherin. Micrometastasis was found more frequently in a pathological T2 status and in the tumors with a negative expression of alpha-catenin. Beta-catenin and gamma-catenin expressions were found less and more frequently in SQ, respectively. A univariate and multivariate survival analysis demonstrated that old age, pathological T2 status, and micrometastasis were independently associated with an increased risk of poor survival in the patients who underwent a surgical resection of stage I NSCLC.

CONCLUSIONS

Complicated relationships exist between lymphangiogenesis/micrometastases and adhesion molecules with a specific histology. The detection of lymph nodal micrometastasis by CK may therefore be a useful marker for predicting a poor prognosis in patients who undergo a complete resection of stage I NSCLC.

Phase II, multicenter, uncontrolled trial of single-agent sorafenib in patients with relapsed or refractory, advanced non-small-cell lung cancer

PURPOSE

Sorafenib is an oral multikinase inhibitor that targets the Ras/Raf/MEK/ERK mitogenic signaling pathway and the angiogenic receptor tyrosine kinases, vascular endothelial growth factor receptor 2 and platelet-derived growth factor receptor beta. We evaluated the antitumor response and tolerability of sorafenib in patients with relapsed or refractory, advanced non-small-cell lung cancer (NSCLC), most of whom had received prior platinum-based chemotherapy.

PATIENTS AND METHODS

This was a phase II, single-arm, multicenter study. Patients with relapsed or refractory advanced NSCLC received sorafenib 400 mg orally twice daily until tumor progression or an unacceptable drug-related toxicity occurred. The primary objective was to measure response rate.

RESULTS

Of 54 patients enrolled, 52 received sorafenib. The predominant histologies were adenocarcinoma (54%) and squamous cell carcinoma (31%). No complete or partial responses were observed. Stable disease (SD) was achieved in 30 (59%) of the 51 patients who were evaluable for efficacy. Four patients with SD developed tumor cavitation. Median progression-free survival (PFS) was 2.7 months, and median overall survival was 6.7 months. Patients with SD had a median PFS of 5.5 months. Major grades 3 to 4, treatment-related toxicities included hand-foot skin reaction (10%), hypertension (4%), fatigue (2%), and diarrhea (2%). Nine patients died within a 30-day period after discontinuing sorafenib, and one patient experienced pulmonary hemorrhage that was considered drug related. CONCLUSION Continuous treatment with sorafenib 400 mg twice daily was associated with disease stabilization in patients with advanced NSCLC. The broad activity of sorafenib and its acceptable toxicity profile suggest that additional investigation of sorafenib as therapy for patients with NSCLC is warranted.

Prognostic significance of the expression of vascular endothelial growth factors A, B, C, and D and their receptors R1, R2, and R3 in patients with nonsmall cell lung cancer

BACKGROUND

Lung cancer is the leading cause of cancer death in the world. The objective of this study was to investigate the expression of vascular endothelial growth factors (VEGFs) and their receptors (VEGFRs) in patients with nonsmall cell lung cancer (NSCLC) and its correlation with the prognosis for patients with lung cancer.

METHODS

The expression status of VEGFs and VEGFRs was examined in 48 nonconsecutive specimens of primary lung cancer by immunohistochemistry. Correlations between the expression of VEGFs and VEGFRs and clinicopathologic parameters were analyzed.

RESULTS

Nineteen of 48 samples (39.6%) were moderately/highly immunoreactive for VEGF-A, 6 samples (12.5%) were reactive for VEGF-B, 14 samples (29.2%) were reactive for VEGF-C, 11 samples (22.9%) were reactive for VEGF-D, 20 samples (41.7%) were reactive for VEGFR1, 26 samples (54.2%) were reactive for VEGFR2, 20 samples (41.7%) were reactive for VEGFR3, and 19 samples (39.6%) were reactive for nuclear expression of VEGFR3. Patients with moderate/high VEGF-C, VEGFR1, and VEGFR2 expression had worse survival, whereas patients with moderate/high VEGF-D and nuclear VEGFR3 expression had better survival. After adjusting according to tumor stage, VEGF-B and VEGF-D expression had a significant correlation with worse survival in patients with stage I and II disease. Patients with stage III and IV disease who had VEGFR1 and VEGFR2 expression had worse survival, whereas the expression of VEGF-D was correlated significantly with better survival. Finally, stage, VEGF-D expression, and VEGFR1 expression were significantly independent prognostic predictors.

CONCLUSIONS

The results of the current study indicated that the over-expression of VEGFs and VEGFRs plays an important role in the survival of patients with NSCLC. The inclusion of angiogenic factors in the standard pathologic study of lung cancer may improve the clinical evaluation of patients with NSCLC.

Fluorodeoxyglucose positron emission tomography and tumor marker expression in non-small cell lung cancer

OBJECTIVE

The best current noninvasive surrogate for tumor biology is fluorodeoxyglucose positron emission tomography (FDG-PET). Both FDG-PET maximal standardized uptake values and selected tumor markers have been shown to correlate with stage, nodal disease, and survival in non-small cell lung cancer (NSCLC). However, there are limited data correlating FDG-PET with tumor markers. The purpose of this study was to determine the correlation of tumor marker expression with FDG-PET maximal standardized uptake values in NSCLC.

METHODS

FDG-PET maximal standardized uptake values were calculated in patients with NSCLC (n = 149). No patient had induction chemoradiotherapy. Intraoperative NSCLC tissue was obtained and tissue microarrays were created. Immunohistochemical analysis was performed for 5 known NSCLC tumor markers (glucose transporter 1, p53, cyclin D1, epidermal growth factor receptor, and vascular endothelial growth factor). Each tumor marker was assessed independently by two pathologists using common grading criteria. Subgroup analysis based on histologic characteristics and regional nodal status was performed.

RESULTS

FDG-PET correlated with T classification (P < .0001), N stage (P = .002), and greatest tumor dimension (P < .0001). In addition, increasing maximal standardized uptake values correlated with increased expression of glucose transporter 1 (P < .0001) and p53 (P = .04) in adenocarcinoma. Epidermal growth factor receptor expression correlated with maximal standardized uptake values without predilection for histologic subtype (P = .004).

CONCLUSION

FDG-PET maximal standardized uptake values correlate with an increased expression of glucose transporter 1 and p53 in lung adenocarcinoma, but not squamous cell cancer. Future studies attempting to correlate FDG-PET with tumor biology will need to consider the effect of different tumor histologic types.

Protein expression profiling of vascular endothelial growth factor and its receptors identifies subclasses of hepatocellular carcinoma and predicts survival

PURPOSE

To examine expression profile and prognostic significance of vascular endothelial growth factor (VEGF) and its receptors in hepatocellular carcinoma (HCC) and peritumoral tissue.

METHODS

Expression of VEGF-A, VEGF-C, and VEGF receptor 1(VEGFR-1), VEGFR-2, and VEGFR-3 in tumor and peritumoral liver tissue was studied by immunohistochemistry in a tissue microarray from 107 patients with HCC. Unsupervised hierarchical cluster analyses were conducted to identify relevant clusters.

RESULTS

Staining of VEGF-A, VEGF-C, VEGFR-2, and VEGFR-3 was mostly found on the tumor cells and peritumoral hepatocytes, but VEGFR-1 was mostly expressed in stromal cells. In most of the cases, the expression of VEGF-A, VEGFR-1, VEGFR-2, and VEGFR-3 in was higher in peritumoral liver tissue, while VEGF-C expression was higher in tumor. Unsupervised hierarchical clustering analysis identified four prognostically different clusters, of which cluster A was classified into the "poor prognosis group," and the other three clusters were classified into the "good prognosis group" (P = 0.047). Further analysis with a set of seven markers reproduced the same four cluster groups with significantly different recurrence free probability (RFP) (P = 0.018), and the low RFP group was associated with more intrahepatic satellite lesions. Multivariate analysis showed that classification defined by seven biomarkers was of prognostic significance (P = 0.000).

CONCLUSIONS

Expression of VEGF and its receptors was higher in peritumoral tissue than in tumor in HCC. Seven biomarkers predicted patients' RFP, which consisted of tumoral expression of VEGF-A, VEGFR-1, and VEGF-C as well as peritumoral expression of VEGF-A, VEGFR-1, VEGFR-2, and VEGFR-3.

Molecular control of lymphatic metastasis

The metastatic spread of tumor cells is the most lethal aspect of cancer and often occurs via the lymphatic vasculature. Both experimental tumor models and human clinicopathologic data indicate that growth of lymphatic vessels (lymphangiogenesis) near solid tumors is often associated with lymph node metastasis. Changes in the adhesive properties of lymphatic endothelium near tumors may also facilitate metastatic spread via the lymphatics. Lymphangiogenic growth factors have been identified that promote formation of tumor lymphatics and metastatic spread of tumor cells to lymph nodes. These include the secreted glycoproteins vascular endothelial growth factor-C (VEGF-C) and VEGF-D, which act via their cognate receptor tyrosine kinase VEGF receptor-3 (VEGFR-3) located on lymphatic endothelial cells. Other signaling molecules that have been reported to promote lymphangiogenesis and/or lymphatic metastasis in cancer include VEGF-A, platelet-derived growth factor-BB, and hepatocyte growth factor. However, the quantitative contribution of these proteins to tumor lymphangiogenesis and lymphatic metastasis in different tumor types requires further investigation. In addition, chemokines are thought to play a role in attracting tumor cells and lymphatic vessels to each other. Moreover, it has recently been shown that lymphangiogenic growth factors secreted from a primary tumor can induce lymphangiogenesis in nearby lymph nodes, even before arrival of tumor cells, which may facilitate further metastasis. This article provides an overview of the molecular mechanisms that control lymphatic metastasis and discusses potential therapeutic approaches for inhibiting this process in human cancer.

VEGF-A and VEGFR-3 correlate with nodal status in operable non-small cell lung cancer: inverse correlation between expression in tumor and stromal cells

BACKGROUND

Lymph node metastasis is an essential determinant for stage and clinical management of non-small cell lung cancer (NSCLC). The vascular endothelial growth factors (VEGFs) and receptors (VEGFRs) are fundamental molecules in angiogenesis and lymphangiogenesis. We aimed to explore the correlations between nodal metastasis and the expression of VEGFs and VEGFRs in tumor cells and in tumor-related stroma.

PATIENTS AND METHODS

Tumor tissue samples from 335 resected patients with stage I-IIIA NSCLC were obtained and tissue microarrays were constructed from duplicate cores of tumor cells and surrounding stromal tissue from each resected specimen. Immunohistochemistry was used to evaluate the expression of VEGF-A, VEGF-C, and VEGF-D and VEGFR-1, VEGFR-2 and VEGFR-3.

RESULTS

There were 232 N0 and 103 N+ patients (76 N1, 27 N2). In multivariate analyses, low stromal VEGF-A expression (P=0.018) is associated with N+ status. In tumor cells, strong correlations exist between high VEGF-A expression (P=0.032) and N+ status, and high VEGFR-3 expression (P<0.001) and N2-status.

CONCLUSION

The converse impact by stromal VEGF-A versus tumor cell VEGF-A expression on nodal metastasis may allude the importance of the tumor-stroma interaction when trying to understand lymphatic metastasis in NSCLC.

Expression of vascular endothelial growth factor-C and its receptor in osteosarcomas

Vascular endothelial growth factor-C (VEGF-C) and its receptor, vascular endothelial growth factor receptor-3 (VEGFR-3), have been implicated as important factors in the formation of lymphatic vessels, but its role in osteosarcomas has not yet been fully investigated. This study aims to define the expression of VEGF-C and VEGFR-3 in primary and metastatic osteosarcomas and their relationship to various clinicopathologic parameters. Thirty-three primary osteosarcomas and two pulmonary metastatic samples were immunostained for VEGF-C and VEGFR-3. In addition, VEGF-C and vascular endothelial growth factor-D (VEGF-D) mRNA expression levels in three different human osteosarcoma cell lines and control fibroblasts were evaluated by real-time quantitative polymerase chain reaction (PCR). Both VEGF-C and VEGFR-3 were expressed mainly in the cytoplasm of the tumor cells. Of the 35 patients with osteosarcoma, 16 patients (45.7%) showed strong positive reaction with VEGF-C. Four cases (11.4%) were negative, and 15 cases (42.9%) showed weak immunoreactivity. For VEGFR-3, 12 patients (34.3%) showed strong positive reaction. Fifteen cases (42.9%) were negative, and eight cases (22.8%) showed weak immunoreactivity. A significant, positive correlation (Rs=0.42, p=0.01) was found between the expression of VEGF-C and VEGFR-3 in osteosarcomas. The expression of VEGF-C was significantly associated with the osteoblastic subtype and high histologic grade in osteosarcomas. However, the expression of VEGF-C showed no significant correlation with the presence of metastasis. Expression of VEGFR-3 was not related to any clinicopathologic features analyzed. Two of the three osteosarcoma cell lines tested showed amplification of VEGF-C mRNA compared with control cells. No amplification of VEGF-D was noted in these cell lines. Our data suggest that VEGF-C and its receptor are expressed in osteosarcomas. Although the level of VEGF-C was high, it does not seem to have a direct influence on tumor metastasis in osteosarcomas.

Calcium carbonate nanoparticle delivering vascular endothelial growth factor-C siRNA effectively inhibits lymphangiogenesis and growth of gastric cancer in vivo

A nonviral gene carrier, calcium carbonate (CaCO3) nanoparticle, was evaluated for efficient in vitro and in vivo delivery of small interfering RNA (siRNA) targeting vascular endothelial growth factor-C (VEGF-C). The chemically synthesized CaCO3 nanoparticle has a 58 nm diameter and +28.6 mV positive surface charge. It is capable of forming a CaCO3 nanoparticle-DNA complex and transferring DNA into targeted cells with high transfection efficiency while effectively protecting the encapsulated DNA from degradation. Furthermore, the CaCO3 nanoparticle-DNA complex has no obvious cytotoxicity for SGC-7901 cells, while a liposome-DNA complex exhibited measurable cytotoxicity. SGC-7901 cells transfected with a VEGF-C-targeted siRNA via CaCO3 nanoparticle exhibit significantly reduced VEGF-C expression as measured by real-time PCR and enzyme-linked immunosorbent assay; whereas no decrease in VEGF-C expression is observed in cells treated by control transfection. Transfection of SGC-7901 cells with VEGF-C siRNA via CaCO3 nanoparticle also dramatically suppresses tumor lymphangiogenesis, tumor growth and regional lymph-node metastasis in subcutaneous xenografts. Significant downregulation of VEGF-C messenger RNA expression in a subcutaneous xenograft derived from VEGF-C siRNA-treated SGC-7901 cells was confirmed by real-time PCR as compared to controls. We conclude that CaCO3 nanoparticle is a novel and nonviral system for effective delivery of siRNA for cancer gene therapy.

VEGF-C expression in squamous cell carcinoma and adenocarcinoma of the esophagus

BACKGROUND

Vascular endothelial growth factor C (VEGF-C) is the only factor known to cause lymphangiogenesis. In esophageal cancer the histologic tumor type and lymph node metastasis are independent predictors of recurrence and poor outcome. To evaluate the rule of VEGF-C expression in esophageal cancer, we investigated 113 specimens, 59 squamous cell and 54 adenocarcinomas of the esophagus.

METHODS

The expression of VEGF-C was evaluated using immunohistochemistry (IHC) on 59 paraffin-embedded archival specimens from patients with squamous cell esophageal carcinomas and 54 paraffin-embedded archival specimens of patients with esophageal adenocarcinomas arising in Barrett's mucosa. All patients had a complete tumor resection. A complete and updated follow-up was available for all patients.

RESULTS

The expression of VEGF-C was significantly different between the two histological types of esophageal tumors. Patients with squamous cell carcinoma and lymph node metastases had a significantly higher VEGF-C expression (P < 0.01). In patients with adenocarcinoma of the esophagus there was no correlation between VEGF-C expression and clinicopathological parameters. High VEGF-C expression tended to be correlated with poor survival in squamous cell cancer but not in adenocarcinoma of the esophagus.

CONCLUSIONS

The present study indicates that VEGF-C may play a role in tumor progression via lymphangiogenesis in squamous cell carcinoma of the esophagus. This seems not to be true for the adenocarcinoma of the esophagus. These data could help with the understanding of the different onset and characteristics of lymph node metastasis in squamous cell carcinoma and adenocarcinoma of the esophagus.

Vascular endothelial growth factor-C and its receptor VEGFR-3 in non-small-cell lung cancer: concurrent expression in cancer cells from primary tumour and metastatic lymph node

INTRODUCTION

Investigation of the role of vascular endothelial growth factor-C (VEGF-C) and VEGF receptor-3 (VEGFR-3) in non-small-cell lung cancer (NSCLC) has mainly focused on lymph node (LN) metastasis related to lymphangiogenesis. However, the coexpression of VEGF-C/VEGFR-3 by tumour cells can independently play an important role. The present study was therefore designed to evaluate VEGF-C/VEGFR-3 coexpression in tumour cells from the primary tumour and corresponding LN metastases.

METHODS

VEGF-C and VEGFR-3 expression in cancer cells were evaluated by immunohistochemistry in 92 NSCLC samples and 45 metastatic LNs. Ki67 expression and mitotic index (MI) in tumours and clinicopathological data were analysed concurrently.

RESULTS

VEGFR-3 and VEGF-C expression were observed in 42% and 74% of tumours, respectively. Concurrent expression of VEGF-C and VEGFR-3, observed in 39% of tumours, was significantly associated with a higher proliferation rate and a higher incidence of LN metastases. VEGF-C expression in tumour cells was observed in 100% of metastatic LN and VEGF-C/VEGFR-3 coexpression was observed in 71% of metastatic LN. Finally, concurrent expression of VEGF-C/VEGFR-3 in the primary tumour was associated with poor disease-free survival on univariate analysis.

CONCLUSION

In NSCLC cancer cells, VEGF-C/VEGFR-3 coexpression suggests an autocrine/paracrine loop responsible for a high proliferation rate in tumour cells. As VEGF-C/VEGFR-3 coexpression is very frequent in metastatic LN tumour cells, it can be hypothesised that this coexpression participates in the growth of LN metastasis.

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.

Tumor cell-organ microenvironment interactions in the pathogenesis of cancer metastasis

The process of cancer metastasis is sequential and selective and contains stochastic elements. The growth of metastases represents the endpoint of many lethal events that few tumor cells can survive. Primary tumors consist of multiple subpopulations of cells with heterogeneous metastatic properties, and the outcome of metastasis depends on the interplay of tumor cells with various host factors. The findings that different metastases can originate from different progenitor cells account for the biological diversity that exists among various metastases. Even within a solitary metastasis of proven clonal origin, however, heterogeneity of biological characteristics can develop rapidly. The pathogenesis of metastasis depends on multiple interactions of metastatic cells with favorable host homeostatic mechanisms. Interruption of one or more of these interactions can lead to the inhibition or eradication of cancer metastasis. For many years, all of our efforts to treat cancer have concentrated on the inhibition or destruction of tumor cells. Strategies both to treat tumor cells (such as chemotherapy and immunotherapy) and to modulate the host microenvironment (including the tumor vasculature) should offer additional approaches for cancer treatment. The recent advances in our understanding of the biological basis of cancer metastasis present unprecedented possibilities for translating basic research to the clinical reality of cancer treatment.

Histopathological and lymphangiogenic parameters in relation to lymph node metastasis in early stage oral squamous cell carcinoma

PURPOSE

Lymph node metastasis from oral squamous cell carcinoma (SCC) correlates with a poor prognosis. Therefore, accurate assessment of lymph node status is crucial in treatment planning. Furthermore, prediction of delayed neck metastasis (DNM), especially in early stage tumors with a clinically negative (N0) neck, will determine the need for neck dissection or irradiation. In this study, we assess various clinical, histopathological and lymphangiogenic parameters in early stage oral SCC and their association with DNM.

MATERIALS AND METHODS

Clinical, histological, and immunohistochemical analyses were undertaken for 29 patients with T1N0M0 or T2N0M0 oral SCC affecting the tongue or floor of mouth and correlated with the development of DNM.

RESULTS

Tumor thickness, nuclear pleomorphism, pattern of invasion, and immunohistochemical expression of the lymphangiogenesis-associated molecules VEGFR-3 and VEGF-C were associated with DNM.

CONCLUSIONS

Analysis of these parameters may help to identify patients who would benefit from a neck dissection or irradiation by predicting the likelihood of lymph node metastasis.

Angiogenesis in cancer

New growth in the vascular network is important since the proliferation, as well as metastatic spread, of cancer cells depends on an adequate supply of oxygen and nutrients and the removal of waste products. New blood and lymphatic vessels form through processes called angiogenesis and lymphangiogenesis, respectively. Angiogenesis is regulated by both activator and inhibitor molecules. More than a dozen different proteins have been identified as angiogenic activators and inhibitors. Levels of expression of angiogenic factors reflect the aggressiveness of tumor cells. The discovery of angiogenic inhibitors should help to reduce both morbidity and mortality from carcinomas. Thousands of patients have received antiangiogenic therapy to date. Despite their theoretical efficacy, antiangiogeic treatments have not proved beneficial in terms of long-term survival. There is an urgent need for a new comprehensive treatment strategy combining antiangiogenic agents with conventional cytoreductive treatments in the control of cancer.

Treatment and outcome of 82 patients with angiosarcoma

BACKGROUND

Angiosarcomas are an uncommon type of malignancy that are generally thought to behave usually in a locally aggressive fashion; they often metastasize to distant sites.

METHODS

Patients with a diagnosis of angiosarcoma treated at our institution between 1980 and 2006 were analyzed for patient demographics, tumor characteristics, multimodality treatment, and outcomes.

RESULTS

A total of 82 patients were divided into those with primary and advanced disease. Overall, the median age was 65 (range, 22-91) years, and 44% of patients were women. Median size of tumors was 3.8 cm, and 76% of tumors were intermediate or high grade. Tumors were located throughout the body: 32 cutaneous, 22 deep soft tissues or organs, 10 radiation or lymphedema field, 8 bone, and 7 nonirradiated breast. Of 46 patients with primary disease, all patients underwent surgical resection, 67% received radiotherapy, and 27% received chemotherapy. Five-year disease-specific survival was 60%, and negative prognostic factors included intermediate or high grade, and tumors arising in a radiated or lymphedema field. Of 36 patients with advanced disease, 36% underwent a palliative operation, 78% received radiation, and 58% received chemotherapy. Median survival was just 7.3 months, and cutaneous tumors predicted a better prognosis compared with other sites.

CONCLUSIONS

Primary angiosarcomas treated with aggressive surgical resection and the addition of radiation for close margins or worrisome pathologic features can result in long-term survival in most patients. The role of adjuvant chemotherapy is unclear. Patients with advanced disease have a poor prognosis, but there can be dramatic responses to chemotherapy in a minority of patients.

Antimicrobial and anti-inflammatory activity of four known and one new triterpenoid from Combretum imberbe (Combretaceae)

Combretum imberbe is used widely in Africa inter alia for treating bacterial infections. In addition to four known triterpenoids, 1alpha,3beta-dihydroxy-12-oleanen-29-oic (1), 1-hydroxy-12-olean-30-oic acid (2), 3,30-dihydroxyl-12-oleanen-22-one (3), and 1,3,24-trihydroxyl-12-olean-29-oic acid (4), a new pentacyclic triterpenoid (1alpha,23-dihydroxy-12-oleanen-29-oic acid-3beta-O-2,4-di-acetyl-L-rhamnopyranoside) 5 has been isolated through a bioassay-guided procedure from the leaves of Combretum imberbe. The structures of the compounds were elucidated on the basis of 1D and 2D NMR experiments, as well as mass spectrometric data. All compounds isolated had moderate (62 microg/ml) to strong (16 microg/ml) antibacterial activity (MIC values) against Staphylococcus aureus and Escherichia coli, with 1 and 5 being most active. Compounds 1 and 5 also showed very strong inhibition of 3alpha-hydroxysteroid dehydrogenase with an IC(50) of 0.3 microg/ml. Compound 5 indicated a moderate anti-proliferative (GI(50)=16.5 and 13.2 microg/ml) and cytotoxic activity (CC(50)=17.6 micro/ml) against K-562, L-929 and HeLa cell lines, respectively. The results of this study give credence to the ethnomedicinal use of Combretum imberbe and expand our knowledge on the biological activity of its metabolites.

Overexpression of vascular endothelial growth factor-C correlates with lymph node micrometastasis in submucosal esophageal cancer

Lymph node metastasis, including lymph node micrometastasis (LMM), is one of the most important prognostic factors in esophageal squamous cell carcinoma (ESCC). Vascular endothelial growth factor C (VEGF-C) plays a key role in the process of lymphangiogenesis. We examined VEGF-C expression and tumor microvessel density of the primary tumors in ESCC and analyzed relationships between VEGF-C expression and clinicopathologic findings including LMM in submucosal ESCC. The subjects were 87 patients with submucosal ESCC. Immunohistochemical staining of VEGF-C and CD34 was performed with primary tumors, and staining of cytokeratin was performed with dissected lymph nodes. Microvessel density was calculated from CD34 expression, and LMM was detected by cytokeratin staining. VEGF-C overexpression significantly correlated with depth of tumor invasion, lymphatic invasion, and lymph node metastasis (P < 0.05, P < 0.0001, and P < 0.0001, respectively). High microvessel density also correlated with lymphatic invasion and lymph node metastasis (P < 0.005 and P < 0.05, respectively). LMM was detected in 8 cases and 14 lymph nodes by cytokeratin staining. VEGF-C overexpression and high microvessel density were found in tumors with lymph node metastasis and/or LMM, compared with tumors without nodal metastasis or LMM (P < 0.0001 and P < 0.01, respectively). The present findings indicate that in ESCC with submucosal invasion, VEGF-C overexpression of the primary tumor is a strong high risk factor for lymph node metastasis, including LMM.

Adenomatoid tumour of the liver

An unusual primary adenomatoid tumour arising in the normal liver is described. Hepatectomy was performed, and the patient is alive and free of disease 1 year postsurgery. Grossly, the tumour showed a haemorrhagic cut surface with numerous microcystic structures. Histological examination revealed cystic or angiomatoid spaces of various sizes lined by cuboidal, low-columnar, or flattened epithelioid cells with vacuolated cytoplasm and round to oval nuclei. The epithelioid cells were entirely supported by proliferated capillaries and arteries together with collagenous stroma. Immunohistochemical studies showed that the epithelioid cells were strongly positive for a broad spectrum of cytokeratins (AE1/AE3, CAM5.2, epithelial membrane antigen and cytokeratin 7) and mesothelial markers (calretinin, Wilms’ tumour 1 and D2-40). These cells were negative for Hep par-1, carcinoembryonic antigen, neural cell adhesion molecule, CD34, CD31 and HMB45. Atypically, abundant capillaries were observed; however, the cystic proliferation of epithelioid cells with vacuoles and immunohistochemical profile of the epithelioid element were consistent with hepatic adenomatoid tumour.

Overexpression of vascular endothelial growth factor-C correlates with lymph node micrometastasis in submucosal esophageal cancer

Lymph node metastasis, including lymph node micrometastasis (LMM), is one of the most important prognostic factors in esophageal squamous cell carcinoma (ESCC). Vascular endothelial growth factor C (VEGF-C) plays a key role in the process of lymphangiogenesis. We examined VEGF-C expression and tumor microvessel density of the primary tumors in ESCC and analyzed relationships between VEGF-C expression and clinicopathologic findings including LMM in submucosal ESCC. The subjects were 87 patients with submucosal ESCC. Immunohistochemical staining of VEGF-C and CD34 was performed with primary tumors, and staining of cytokeratin was performed with dissected lymph nodes. Microvessel density was calculated from CD34 expression, and LMM was detected by cytokeratin staining. VEGF-C overexpression significantly correlated with depth of tumor invasion, lymphatic invasion, and lymph node metastasis (P < 0.05, P < 0.0001, and P < 0.0001, respectively). High microvessel density also correlated with lymphatic invasion and lymph node metastasis (P < 0.005 and P < 0.05, respectively). LMM was detected in 8 cases and 14 lymph nodes by cytokeratin staining. VEGF-C overexpression and high microvessel density were found in tumors with lymph node metastasis and/or LMM, compared with tumors without nodal metastasis or LMM (P < 0.0001 and P < 0.01, respectively). The present findings indicate that in ESCC with submucosal invasion, VEGF-C overexpression of the primary tumor is a strong high risk factor for lymph node metastasis, including LMM.

Overexpression of vascular endothelial growth factor-C correlates with lymph node micrometastasis in submucosal esophageal cancer

Lymph node metastasis, including lymph node micrometastasis (LMM), is one of the most important prognostic factors in esophageal squamous cell carcinoma (ESCC). Vascular endothelial growth factor C (VEGF-C) plays a key role in the process of lymphangiogenesis. We examined VEGF-C expression and tumor microvessel density of the primary tumors in ESCC and analyzed relationships between VEGF-C expression and clinicopathologic findings including LMM in submucosal ESCC. The subjects were 87 patients with submucosal ESCC. Immunohistochemical staining of VEGF-C and CD34 was performed with primary tumors, and staining of cytokeratin was performed with dissected lymph nodes. Microvessel density was calculated from CD34 expression, and LMM was detected by cytokeratin staining. VEGF-C overexpression significantly correlated with depth of tumor invasion, lymphatic invasion, and lymph node metastasis (P < 0.05, P < 0.0001, and P < 0.0001, respectively). High microvessel density also correlated with lymphatic invasion and lymph node metastasis (P < 0.005 and P < 0.05, respectively). LMM was detected in 8 cases and 14 lymph nodes by cytokeratin staining. VEGF-C overexpression and high microvessel density were found in tumors with lymph node metastasis and/or LMM, compared with tumors without nodal metastasis or LMM (P < 0.0001 and P < 0.01, respectively). The present findings indicate that in ESCC with submucosal invasion, VEGF-C overexpression of the primary tumor is a strong high risk factor for lymph node metastasis, including LMM.

Overexpression of vascular endothelial growth factor-C correlates with lymph node micrometastasis in submucosal esophageal cancer

Lymph node metastasis, including lymph node micrometastasis (LMM), is one of the most important prognostic factors in esophageal squamous cell carcinoma (ESCC). Vascular endothelial growth factor C (VEGF-C) plays a key role in the process of lymphangiogenesis. We examined VEGF-C expression and tumor microvessel density of the primary tumors in ESCC and analyzed relationships between VEGF-C expression and clinicopathologic findings including LMM in submucosal ESCC. The subjects were 87 patients with submucosal ESCC. Immunohistochemical staining of VEGF-C and CD34 was performed with primary tumors, and staining of cytokeratin was performed with dissected lymph nodes. Microvessel density was calculated from CD34 expression, and LMM was detected by cytokeratin staining. VEGF-C overexpression significantly correlated with depth of tumor invasion, lymphatic invasion, and lymph node metastasis (P < 0.05, P < 0.0001, and P < 0.0001, respectively). High microvessel density also correlated with lymphatic invasion and lymph node metastasis (P < 0.005 and P < 0.05, respectively). LMM was detected in 8 cases and 14 lymph nodes by cytokeratin staining. VEGF-C overexpression and high microvessel density were found in tumors with lymph node metastasis and/or LMM, compared with tumors without nodal metastasis or LMM (P < 0.0001 and P < 0.01, respectively). The present findings indicate that in ESCC with submucosal invasion, VEGF-C overexpression of the primary tumor is a strong high risk factor for lymph node metastasis, including LMM.

Tumor lymphangiogenesis and metastatic spread-new players begin to emerge

The metastatic spread of tumor cells is the most lethal aspect of cancer and can occur via various routes, including the lymphatic vasculature. Studies of tumor models in animals and clinicopathological data have indicated that growth of lymphatic vessels (lymphangiogenesis) in the vicinity of solid tumors may contribute to lymphatic metastasis. Research over the past 5 years has identified a range of lymphangiogenic growth factors that could conceivably play a role in promoting tumor lymphangiogenesis and lymphatic metastasis. The most extensively studied signaling system that promotes lymphangiogenesis in tumors involves the secreted lymphangiogenic proteins vascular endothelial growth factor-C (VEGF-C) and VEGF-D, and their cognate receptor on lymphatic endothelium VEGF receptor-3 (VEGFR-3). More recent studies have identified other signaling molecules that can also promote lymphangiogenesis in vivo, including hepatocyte growth factor and members of the fibroblast growth factor, angiopoietin, platelet-derived growth factor and insulin-like growth factor families of secreted proteins. This article provides an overview of the molecular mechanisms that control lymphangiogenic signaling, emphasizing the more recently identified lymphangiogenic growth factors and the roles they may play in cancer biology. Molecular approaches for inhibiting lymphangiogenic signaling in cancer, designed to restrict tumor metastasis, are also examined.

Immunohistochemical markers of prognosis in non-small cell lung cancer: a review and proposal for a multiphase approach to marker evaluation

Characteristics of the tumour that affect and predict the survival outcome of patients with cancer are prognostic markers for cancer. In non-small cell lung carcinoma (NSCLC), stage is the main determinant of prognosis and the basis for deciding options for treatment. Patients with early-stage tumour are treated by complete surgical resection, which is curative in 40-70% of patients. That there are other factors important in determining the biology of these tumours, especially genes that have a role in metastasis, is indicated. Such factors could potentially be used to further classify patients into groups according to substages that may be treated differently. During the past decade, a large number of proteins that are putatively important in carcinogenesis and cancer biology have been studied for their prognostic value in NSCLC, but none of them have been proved to be sufficiently useful in clinical diagnosis. Several markers (epidermal growth factor receptor, human epidermal growth factor receptor 2, Ki-67, p53 and Bcl-2) have been studied exhaustively. Ki-67, p53 and Bcl-2 are suggested to be important but weak prognostic markers, by meta-analyses of the results. Cyclin E, vascular endothelial growth factor A, p16(INK4A), p27(kip1) and beta-catenin are promising candidates, but require further study in large randomised clinical trial samples by using standardised assays and scoring systems. Some issues and inconsistencies in the reported studies to date are highlighted and discussed. A guideline for a multi-phase approach for conducting future studies on prognostic immunohistochemistry markers is proposed here.

Local balance of transforming growth factor-beta1 secreted from cholangiocarcinoma cells and stromal-derived factor-1 secreted from stromal fibroblasts is a factor involved in invasion of cholangiocarcinoma

Tumor-stromal interactions are important for the progression of malignant tumors. The purpose of the present study was to examine interactions of cholangiocarcinoma (CC) cells and stromal fibroblasts with respect to stromal-derived factor-1 (SDF-1) and transforming growth factor (TGF)-beta1. Two cell lines of CC (HuCCT-1 and CCKS-1) and WI-38 fibroblast cell line were used for cell culture, and 12 CC tissue specimens for immunohistochemical studies. Invasion of CC cells was increased significantly by the supernatant from fibroblast cultures, but not by the supernatant from fibroblasts cocultured with CC cells. Expression of SDF-1 in cultured fibroblasts was downregulated by TGF-beta1 treatment, and coculture with CC cells and anti-TGF-beta1 neutralizing antibody restored the decreased SDF-1 expression, suggesting that TGF-beta1 secreted from CC cells might have reduced the expression of SDF-1 by fibroblasts and might have reduced the increased invasion of CC cells induced by the supernatant from fibroblasts. Immunohistochemical expression of TGF-beta1 in CC cells was focal or negative and that of SDF-1 was evident in stromal fibroblasts at the invasive front of CC. In conclusion, local mutual influence of TGF-beta1 secreted from carcinoma cells and SDF-1 expressed by stromal fibroblasts may be involved in invasion of CC cells.

The balance of VEGF-C and VEGFR-3 mRNA is a predictor of lymph node metastasis in non-small cell lung cancer

A positive association between vascular endothelial growth factor-C (VEGF-C) expression and lymph node metastasis has been reported in several cancers. However, the relationship of VEGF-C and lymph node metastasis in some cancers, including non-small cell lung cancer (NSCLC), is controversial. We evaluated the VEGF-C and vascular endothelial growth factor receptor-3 (VEGFR-3) expression in NSCLC samples from patients who had undergone surgery between 1998 and 2002 using real-time quantitative RT–PCR and immunohistochemical staining. We failed to find a positive association between VEGF-C and VEGFR-3 mRNA expression and lymph node metastasis in NSCLC. An immunohistological study demonstrated that VEGF-C was expressed not only in cancer cells, but also in macrophages in NSCLC, and that VEGFR-3 was expressed in cancer cells, macrophages, type II pneumocytes and lymph vessels. The VEGF-C/VEGFR-3 ratio of the node-positive group was significantly higher than that of the node-negative group. Immunohistochemical staining showed that VEGFR-3 was mainly expressed in cancer cells. The immunoreactivity of VEGF-C and VEGFR-3 was roughly correlated to the mRNA levels of VEGF-C and VEGFR-3 in real-time PCR. VEGF-C mRNA alone has no positive association with lymph node metastasis in NSCLC. The VEGF-C/VEGFR-3 ratio was positively associated with lymph node metastasis in NSCLC. This suggests that VEGF-C promotes lymph node metastasis while being influenced by the strength of the VEGF-C autocrine loop, and the VEGF-C/VEGFR-3 ratio can be a useful predictor of lymph node metastasis in NSCLC.

Possible regulation of migration of intrahepatic cholangiocarcinoma cells by interaction of CXCR4 expressed in carcinoma cells with tumor necrosis factor-alpha and stromal-derived factor-1 released in stroma

Intrahepatic cholangiocarcinoma (ICC) is highly fatal because of early invasion, widespread metastasis, and lack of an effective therapy. We examined roles of CXCR4 and its ligand, stromal cell-derived factor (SDF)-1, in migration of ICC with respect to tumor-stromal interaction by using two ICC cell lines, a fibroblast cell line (WI-38), and 28 human ICC tissues. The two ICC cell lines expressed CXCR4 mRNA and protein, and WI-38 fibroblasts expressed SDF-1 mRNA and protein. Migration of cultured ICC cells in Matrigel was induced by co-culture with WI-38 fibroblasts and by incubation with SDF-1. Anti-SDF-1 antibody suppressed migration, demonstrating that SDF-1 released from WI-38 fibroblasts was responsible for this migration. Tumor necrosis factor (TNF)-alpha pretreatment of ICC cells up-regulated CXCR4 mRNA and protein expression in a concentration-dependent manner. Administration of SDF-1 and TNF-alpha increased synergistically ICC cell migration, which was suppressed by the CXCR4 antagonist AMD3100. In ICC tissue, TNF-alpha was mainly expressed in infiltrated macrophages, CXCR4 in ICC cells, and SDF-1 in stromal fibroblasts. In conclusion, the interaction of SDF-1 released from fibroblasts and CXCR4 expressed on ICC cells may be actively involved in ICC migration, and TNF-alpha may enhance ICC cell migration by increasing CXCR4 expression. CXCR4 could be a therapeutic target to prevent ICC invasion.

Expression of vascular endothelial growth factor-C and its receptor in invasive micropapillary carcinoma of the breast

Invasion to lymphatic vessels and metastasis to lymph nodes are frequent complications in invasive micropapillary carcinoma (IMPC) of human breast cancer. Vascular endothelial growth factor-C (VEGF-C) and its receptor, VEGFR-3 have been implicated as the important factors in the formation of lymphatic vessels and recent experimental evidence strongly suggests that lymphangiogenesis in tumor promotes lymphatic metastasis. To clarify the mechanism of its occurrence, the expression of VEGF-C, VEGFR-3 and lymphatic vessel density (LVD) was examined in 40 cases of IMPC (pure and mixed type) and in 40 cases of pseudo-IMPC. Cytoplasmic expression of VEGF-C and VEGFR-3 were more frequent in tumor cells of IMPC compared to those of pseudo-IMPC. A significant positive correlation was found between the expression of VEGF-C and VEGFR-3 in both IMPC and pseudo-IMPC. The expression of VEGF-C was also significantly associated with higher peritumoral LVD, lymphatic invasion and number of lymph node metastasis in IMPC. These findings suggest that VEGF-C promotes the proliferation of peritumoral lymphatic vessels and that lymphatic invasion and metastasis to lymph nodes are frequently induced in IMPC of breast.

Current status and perspective of angiogenesis and antivascular therapeutic strategy: non-small cell lung cancer

Lung cancer is the leading cause of cancer death worldwide, and most patients die of metastatic disease. Angiogenesis, namely, neovascularization from preexisting vasculature, is necessary for tumor growth in both primary and distant organs to supply oxygen and nutrition. Angiogenesis consists of sprouting and nonsprouting (the enlargement, splitting, and fusion of preexisting vessels) processes, and both can occur concurrently. The growth of non-small cell lung cancer (NSCLC), which accounts for more than 80% of all lung cancers, is usually dependent on angiogenesis, which is regulated by complex mechanisms in the presence of various angiogenesis-related molecules. Vascular endothelial growth factor (VEGF), also known as vascular permeability factor (VPF), is one of the most potent angiogenic molecules, while also regulating both angiogenesis and vascular permeability and hence promoting tumor progression and the development of malignant pleural effusions in NSCLC. Recent clinical trials showed that the anti-VEGF antibody bevacizumab, combined with standard first-line chemotherapy, provided a statistically and clinically significant survival advantage with tolerable toxicity. In addition, the combined use of the anti-VEGF antibody with an inhibitor of epidermal growth factor receptor (EGFR) has also shown favorable antitumor efficiency. These successes proved the validity of an antivasculature strategy for NSCLC. Furthermore, a large number of antivasculature agents have been shown to be effective against multiple targets. The efficiency of these compounds is currently being investigated in clinical trials for NSCLC.

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.

Increased expression of vascular endothelial growth factor C in papillary thyroid carcinoma correlates with cervical lymph node metastases

PURPOSE

Despite recent studies showing that vascular endothelial growth factor C (VEGF-C) mRNA is up-regulated in papillary thyroid carcinoma (PTC), the role of VEGF-C in lymph node metastasis is still unclear. The aim of this study is to investigate the expression pattern of VEGF-C immunoreactive protein in PTC and its relationship with cervical lymph node metastasis.

EXPERIMENTAL DESIGN

Tissue samples were obtained from 39 specimens of PTC (20 with and 19 without lymph node metastasis) as well as 20 benign thyroid nodules. Overexpression of the VEGF-C protein was evaluated by immunoblotting with specific anti-VEGF-C antibody in paired tumor and nontumor tissues from PTC. The data were compared with patients' clinicopathologic features and lymph node metastasis. Immunohistochemical staining was done on selected paraffin sections to determine cellular localization of VEGF-C and to assess flt-4 (or VEGFR-3)-positive vessel density in PTC lesions.

RESULTS

Overexpression of VEGF-C was detected in 69% of the PTC and in 5% of the benign thyroid specimens. When comparing between the metastatic and nonmetastatic groups of PTC, a higher expression level of VEGF-C was detected in both the tumor (P = 0.004) and adjacent nontumor tissues (P = 0.011). Positive immunostaining for VEGF-C was confirmed in PTC tumor tissues and metastatic lymph nodes, which correlated with flt-4-positive vessel density in tumor and peritumor tissues. The increased expression of VEGF-C protein in PTC is associated with lymph node metastasis (P = 0.004) and lymphovascular permeation (P = 0.001) but is independent of other clinicopatholgic variables.

CONCLUSIONS

The VEGF-C immunoreactive protein is overexpressed in PTC lesions, which correlates with lymph node metastases. VEGF-C expression may play a role in lymphangiogenesis of PTC and further study is necessary to evaluate the clinical application of VEGF-C as a molecular marker for tumor metastases to cervical lymph nodes.

Angiogenesis in non-small cell lung cancer: The prognostic impact of neoangiogenesis and the cytokines VEGF and bFGF in tumours and blood

BACKGROUND

Due to a dismal prognosis of advanced lung cancer, novel screening tools and more effective treatments are clearly needed. Lately, an increasing number of tumour-released angiogenic cytokines which affect vessel formation, tumour growth, invasion, and metastasis have been identified. Vascular endothelial growth factors (VEGFs) and basic fibroblast growth factor (bFGF) are among the most important angiogenic factors. Based on available literature, we have explored the mechanisms of angiogenesis and its prognostic significance in non-small cell lung cancer, estimated by microvessel density (MVD) and the presence of VEGF and bFGF in the tumour and blood from NSCLC patients.

METHODS

Several comprehensive Pubmed searches for the period January 1993 to May 2005 were performed using strategic combinations of the terms non-small cell lung cancer, angiogenesis, vascular endothelial growth factor, basic fibroblast growth factor, tumour expression, microvessel density, circulating, and serum.

RESULTS

NSCLC neoangiogenesis, as measured by MVD, and tumour expression of VEGF are poor prognostic factors for survival (MVD, HR 1.8-2.0; VEGF, HR 1.5). bFGF tumour expression is also associated with poor survival and more aggressive disease. When evaluating the prognostic impact of elevated VEGF levels in blood, 10 of 16 studies (63%) indicated a negative prognostic impact. Of five studies on the prognostic value of circulating bFGF, three studies reported a negative prognostic impact, while one indicated bFGF as a good prognostic factor and one was inconclusive.

CONCLUSION

Angiogenic factors are poor prognostic indicators for tumour aggressiveness and survival in NSCLC. Assessments of circulating levels of VEGF and possibly bFGF may be valuable future tools for treatment planning and monitoring of treatment effect and relapse. First, however, these blood tests need to be standardised and validated in large-scale prospective clinical trials.

Results of Initial Operations in Non–Small Cell Lung Cancer Patients With Single-Level N2 Disease

BACKGROUND

There is still debate regarding the use of surgery in the management of non-small cell lung cancer patients with N2 disease. The primary aim of the present study was analysis of the results of initial operations in non-small cell lung cancer patients with single-level N2 disease.

METHODS

Ninety-four patients with the disease who underwent initial surgery consisting of complete resection of the primary site plus systematic lymphadenectomy were examined. We also immunohistochemically examined lymphatic vessel density and vascular endothelial growth factor-C expression.

RESULTS

The overall 5- and 10-year survival rates for the 94 patients were 27.1% and 12.1%, respectively, with a median survival of 22 months. When stratified by skipping status, the 5-year survival rates for the patients in skip-N2 and non-skip-N2 groups were 33.4% and 19.8%, respectively (p = 0.0189). Skip metastasis, T factor, subcarinal lymph node metastasis, and adjuvant chemotherapy were recognized as independent prognostic indicators. In both skip-N2 and non-skip-N2 groups, distant relapse was the dominant pattern of recurrence. Although the peritumoral lymphatic vessel density was associated with vascular endothelial growth factor-C expression in tumors, the lymphangiogenic profile appeared to be different between skip-N2 and non-skip-N2 tumors, suggesting different nodal metastatic process.

CONCLUSIONS

Lung cancer patients with single-level N2 disease are an oncologically heterogeneous cohort. Although further studies involving randomized comparisons are required, the poor outcomes found here indicate that the initial operation has yet to be validated for patients with this disease.

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.

Clinical significance of vascular endothelial growth factor-C and vascular endothelial growth factor receptor 3 in patients with T1 lung adenocarcinoma

BACKGROUND

Vascular endothelial growth factor-C (VEGF-C) plays an important role in lymphangiogenesis and activates VEGF receptor-3 (VEGFR-3). Lymphatic spread is an important prognostic factor in patients with lung adenocarcinoma. The aim of the current study was to determine whether the expression of VEGF-C and VEGFR-3 correlates with clinicopathologic factors and prognosis in patients with TNM classification T1 lung adenocarcinoma.

METHODS

The authors conducted a retrospective review of 129 consecutive patients who underwent complete resection for T1 lung adenocarcinoma. Immunohistochemical staining for VEGF-C, VEGF, VEGFR-3, CD34 (microvessels), tryptase (mast cells), and CD68 (macrophages) was performed to statistically analyze clinicopathologic implications of VEGF-C and VEGFR-3 status.

RESULTS

Of 129 patients with T1 lung adenocarcinoma, 56 (43.3%) patients were positive for tumor-cell VEGF-C and 73 (56.6%) and 69 (53.5%) patients were positive for tumor-cell and endothelial-cell VEGFR-3, respectively. Patients with positive staining for tumor-cell VEGF-C showed significantly less favorable survival rates than patients with negative staining (P = 0.031). The survival rates of patients with positive staining for tumor-cell and endothelial-cell VEGFR-3 were significantly lower than those with negative staining (P = 0.0034 and P = 0.0020, respectively). Patients with positive staining for both tumor-cell VEGF-C and endothelial-cell VEGFR-3 exhibited the most unfavorable prognoses. Multivariate analysis demonstrated that coexpression of tumor-cell VEGF-C and endothelial-cell VEGFR-3 was an independent negative prognostic factor (P = 0.0129) as well as N factor (P = 0.0020).

CONCLUSIONS

VEGF-C and VEGFR-3 status may be indicative of survival rates for patients with T1 lung adenocarcinoma.

Expression of vascular endothelial growth factor C (VEGF-C) and VEGF receptor-3 in human prostate cancer is associated with regional lymph node metastasis

BACKGROUND

Vascular endothelial growth factor C (VEGF-C) and its receptor, VEGFR-3, have been implicated as important factors in the formation of lymphatic vessels and recent evidence suggests that tumor lymphangiogenesis promotes lymphatic metastasis.

METHODS

The expression of VEGF-C and VEGFR-3 was examined in 22 human prostate cancer specimens with immunohistochemistry. A semi-quantitative scoring system was used for evaluation of staining.

RESULTS

Expression of VEGF-C was stronger in prostate cancer areas in comparison to adjacent benign glands. In addition, patients with lymph node metastases had a significantly higher expression of VEGF-C than patients without lymph node metastases. Interestingly, VEGFR-3 was expressed in malignant prostate epithelial cells and its expression was significantly higher in the lymph node positive group compared to the lymph node negative group.

CONCLUSIONS

The results of the present study indicate that increased expression of VEGF-C and VEGFR-3 play a role in prostate cancer progression and in metastasis to regional lymph nodes.

Flt-4-positive endothelial cell density and its clinical significance in non-small cell lung cancer

PURPOSE

Experimental studies have revealed that fms-like tyrosine kinase (Flt)-4 plays important roles in lymphangiogenesis in malignant tumors, but the clinical significance remains unclear. We assessed Flt-4 expression in tumor cells and in endothelial cells in correlation with clinical outcomes in non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

A total of 206 consecutive patients with resected pathological stage I-IIIA NSCLC were reviewed. Expression of Flt-4 was examined immunohistochemically, and Flt-4-positive microvessels were quantitatively evaluated (Flt-4-positive endothelial cell density).

RESULTS

There was no significant correlation between Flt-4-positive endothelial cell density and any characteristic of patients including nodal metastases. A significant correlation between Flt-4-positive endothelial cell density and Flt-4 status in tumor cells was documented (P < 0.001), but there was no significant difference in the mean Flt-4-positive endothelial cell density according to vascular endothelial growth factor-C or -D status in tumor cells. The 5-year survival rate for higher Flt-4-positive endothelial cell density tumor (56.4%) was significantly lower than that of lower Flt-4-positive endothelial cell density tumor (69.0%, P = 0.046); the prognostic significance was enhanced in pIIIA-N2 patients (5-year survival rates, 18.8% for higher Flt-4-positive endothelial cell density tumor and 50.0% for lower Flt-4-positive endothelial cell density tumor, respectively; P = 0.012). A multivariate analysis confirmed that higher Flt-4-positive endothelial cell density was a significant and independent prognostic factor (P = 0.019). CD34-positive vessel density or Flt-4 status in tumor cells was not a significant prognostic factor.

CONCLUSIONS

Flt-4-positive endothelial cell density, not Flt-4 status in tumor cells, was a significant prognostic factor in NSCLC.

Vascular endothelial growth factor-C (VEGF-C) expression predicts lymph node metastasis of transitional cell carcinoma of the bladder

PURPOSE

It has been found that expression of vascular endothelial growth factor-C (VEGF-C) in several carcinomas is significantly associated with angiogenesis, lymphangiogenesis and regional lymph node metastasis. However, VEGF-C expression in bladder transitional cell carcinoma (TCC) has not yet been reported. To elucidate the role of VEGF-C in bladder TCC, we examined VEGF-C expression in bladder TCC and pelvic lymph node metastasis specimens obtained from patients who underwent radical cystectomy.

METHODS

Eighty-seven patients who underwent radical cystectomy for clinically organ-confined TCC of the bladder were enrolled in the present study. No neoadjuvant treatments, except transurethral resection of the tumor, were given to these patients. The VEGF-C expressions of 87 bladder tumors and 20 pelvic lymph node metastasis specimens were examined immunohistochemically and the association between VEGF-C expression and clinicopathological factors, including angiogenesis as evaluated by microvessel density (MVD), was also examined.

RESULTS

Vascular endothelial growth factor-C expression was found in the cytoplasm of tumor cells, but not in the normal transitional epithelium. Vascular endothelial growth factor-C expression was significantly associated with the pathological T stage (P = 0.0289), pelvic lymph node metastasis (P < 0.0001), lymphatic involvement (P = 0.0008), venous involvement (P = 0.0002) and high MVD (P = 0.0043). The multivariate analysis demonstrated that VEGF-C expression and high MVD in bladder TCC were independent risk factors influencing the pelvic lymph node metastasis. Moreover, the patients with VEGF-C-positive tumors had significantly poorer prognoses than those with the VEGF-C-negative tumors (P = 0.0087) in the univariate analysis. The multivariate analysis based on Cox proportional hazard model showed that the independent prognostic factors were patient age (P = 0.0132) and pelvic lymph node metastasis (P = 0.0333).

CONCLUSION

The present study suggests that VEGF-C expression is an important predictive factor of pelvic lymph node metastasis in bladder cancer patients.

Detection and clinical significance of bone marrow micrometastases in patients undergoing liver transplantation for hepatocellular carcinoma

BACKGROUND

Existing methods of selecting patients with hepatocellular carcinoma (HCC) for liver transplantation rely on computed tomography and magnetic resonance imaging, which fail to detect vascular invasion or micrometastases. Vascular invasion cannot be assessed pretransplant because of the risks of tumor biopsy. Pretransplant detection of micrometastases in bone marrow is an alternative method that may identify patients at risk of recurrence and permit better organ allocation. The authors' aim was to develop an accurate method of detecting hepatocellular carcinoma micrometastases that may have a clinical role in pretransplant assessment.

METHODS

Iliac crest bone marrow was sampled from 18 patients with HCC (before liver transplantation) and 14 controls (cirrhosis, 9; hematologic disorders, 5). Mononuclear bone marrow fractions were evaluated for the presence of micrometastases by immunocytochemistry (ICC) using Hep Par-1 (HPICC) and Glypican-3 (GPICC), and by reverse-transcriptase (RT) polymerase chain reaction using two primer pairs targeting albumin (Alb1RT and Alb2RT) and one pair targeting alpha-fetoprotein (AFPRT). Each marker was compared in terms of (1) specificity and (2) positive and negative predictive values for tumor recurrence.

RESULTS

The specificity of each marker for detecting HCC micrometastases were as follows: HPICC, 93%; GPICC, 92%; Alb1RT, 33%; Alb2RT, 59%; and AFPRT, 0%. The positive (negative) predictive values for HPICC, GPICC, and Alb2RT for posttransplant tumor recurrence were 42% (100%), 40% (73%), and 0% (43%), respectively. HPICC-positive micrometastases were identified in all patients with postoperative tumor recurrence (n=5) and in 75% of patients with microscopic vascular invasion.

CONCLUSIONS

Detection of HCC micrometastases in bone marrow of potential liver transplant candidates is a potentially useful technique that may provide important prognostic information without the need for preoperative tumor biopsy. The authors' preliminary data indicate that HPICC is a promising immunocytochemical marker for HCC micrometastases, and larger studies are needed to confirm its clinical role.