High and Low Grade Oligodendrogliomas (ODG): Correlation of Amino-Acid and Glucose Uptakes Using PET and Histological Classifications

Classification and treatment strategy of oligodendrogliomas (ODG) remain controversial. Imaging relies essentially on contrast enhancement using CT or MRI. The aim of our study was to use positron emission tomography (PET) using [18F]-flurodeoxyglucose (FDG) and [11C]-L-methyl-methionine (MET) to evaluate metabolic characteristics of ODG. We studied 19 patients with proven ODG, comparing standardized uptake values (SUV) and maximal tumor/contralateral normal tissues ratios (T/N). Imaging findings were compared with WHO, Smith and Daumas-Duport classifications. Uptake of FDG was decreased only in 8 patients, independently of grading, while MET uptake was always increased. MET uptake was significantly higher for high grade tumors grouped according to Smith or Daumas-Duport classifications, while no significant difference in MET uptake was found when using WHO classification. A different correlation was found between FDG and MET uptakes in normal tissues and high grade tumors. A trend for improved progression free survival was found for tumors that lacked contrast enhancement on MRI or those showing low FDG or MET uptake. In conclusion, MET appeared more sensitive than FDG to detect proliferation in ODG. The preferential protein metabolism, already noticeable for low-grade tumor, correlated with glucose metabolism and helped to separate, in vivo, high and low grade tumors.     

Clinicopathological evaluation of 78 astrocytomas in Taiwan with emphasis on a simple grading system

Summary The grading systems of astrocytic tumors have long been the subject of controversy. A simple, objective and effective grading method is urgently needed for the evaluation of prognosis and the planning of treatment. This study investigated the relationship of clinical prognostic factors to the grading method of Daumas-Duport. This method determines the grade of tumor based on the presence or absence of four morphological criteria: nuclear atypia, mitosis, endothelial proliferation, and necrosis. A total of 143 astrocytic tumors were reviewed and screened, of which 65 ordinary and 13 pilocytic astrocytomas were selected for grading and comparison. Among ordinary astrocytomas, the grading method distinguished 9.2% grade 1, 26.2% grade 2, 36.9% grade 3, and 27.6% grade 4. At least 2-year follow-up was available on all surviving patients. Median survival was 57, 32, 12.5, and 8 months in grades 1, 2, 3, and 4 tumors, respectively. By a multiple regression model and analysis of variance, grade is significantly associated with survival (total regression coefficient r = 0.711). Age lost its significance on survival after multiple regression analysis. Sex, location, and surgical procedure were all unrelated to survival after regression. The age distribution and survival of patients with pilocytic astrocytomas revealed that this is a distinct disease entity and should not be admixed with ordinary astrocytomas in a grading scheme.This paper is part of his master thesis.     

Vascular endothelial growth factor (VEGF) mRNA expression in human tumor models of different histologies

Background: Vascular endothelial growth factor (VEGF) is a polypeptidewith specific effects on endothelial cell growth and blood vesselpermeability. Recent studies demonstrated a key role for VEGFin tumor neovascularization, which is a prerequisite for tumorproliferation and metastasis Patients and methods: We studied the expression of VEGF mRNAin a panel of 65 different human tumor xeno-grafts of varioushistologies using Northern and slot blot analyses. Analysisof vessel density was performed morphologically and after immunohistochemicalstaining of endothelial cells Results: High expression levels were observed in 22/65 tumors.In melanoma, colorectal, gastric, breast and lung cancers onlysingle tumors showed strong expression signals, whereas 7/10renal cell carcinoma (RCC) xenografts demonstrated high levelsof VEGF mRNA. Vessel density analysis revealed a clear correlationof VEGF mRNA expression with vascularization in RCC (p - 0.0048).Patient survival time was compared for tumors showing high versuslow expression values. The overall 5-year survival rate wassignificantly lower for patients with high expression of VEGFmRNA (p - 0.0306) Conclusions: These data support the hypothesis that tumor cellsof various histologies secrete VEGF, which acts as a paracrinefactor to induce endothelial cell proliferation and vessel formationand mediates tumor progression VEGF, VPF, angiogenesis, vascularization, renal cell carcinoma, human tumor xenografts     

Vascular Endothelial Growth Factor (VEGF) in Astrocytic Gliomas – A Prognostic Factor?

Survival in astrocytic gliomas is closely related to WHO tumor grade. Within one tumor grade, especially in grade II and III tumors, the clinical course is variable and can hardly be predicted by histological criteria. Neovascularization is a neuropathological hallmark in high grade gliomas and angiogenic factors may play an important role in malignant tumor progression. Therefore, 162 primary astrocytic gliomas (57 astrocytomas WHO grade II, 27 astrocytomas WHO grade III and 78 glioblastomas WHO grade IV) were investigated immunohistochemically for expression of vascular endothelial growth factor (VEGF), which is considered to represent the main angiogenic factor in astrocytic gliomas. Clinical data known to influence prognosis were documented. VEGF expression was found in 21 of 57 astrocytomas WHO grade II (36.8%), in 18 of 27 astrocytomas WHO grade III (66.7%) and in 50 of 78 glioblastomas (64.1%). A strong correlation between VEGF expression and survival was found within the whole study group, however, within one tumor grade no such correlation was obvious. In a multifactorial analysis VEGF expression was not found to be an independent prognostic factor in astrocytic gliomas.     

Neuropilin-1 promotes human glioma progression through potentiating the activity of the HGF/SF autocrine pathway

Neuropilin-1 (NRP1) functions as a coreceptor through interaction with plexin A1 or vascular endothelial growth factor (VEGF) receptor during neuronal development and angiogenesis. NRP1 potentiates the signaling pathways stimulated by semaphorin 3A and VEGF-A in neuronal and endothelial cells, respectively. In this study, we investigate the role of tumor cell-expressed NRP1 in glioma progression. Analyses of human glioma specimens (WHO grade I-IV tumors) revealed a significant correlation of NRP1 expression with glioma progression. In tumor xenografts, overexpression of NRP1 by U87MG gliomas strongly promoted tumor growth and angiogenesis. Overexpression of NRP1 by U87MG cells stimulated cell survival through the enhancement of autocrine hepatocyte growth factor/scatter factor (HGF/SF)/c-Met signaling. NRP1 not only potentiated the activity of endogenous HGF/SF on glioma cell survival but also enhanced HGF/SF-promoted cell proliferation. Inhibition of HGF/SF, c-Met and NRP1 abrogated NRP1-potentiated autocrine HGF/SF stimulation. Furthermore, increased phosphorylation of c-Met correlated with glioma progression in human glioma biopsies in which NRP1 is upregulated and in U87MG NRP1-overexpressing tumors. Together, these data suggest that tumor cell-expressed NRP1 promotes glioma progression through potentiating the activity of the HGF/SF autocrine c-Met signaling pathway, in addition to enhancing angiogenesis, suggesting a novel mechanism of NRP1 in promoting human glioma progression.     

Inhibition of VEGF receptors significantly impairs mammary cancer growth in C3(1)/Tag transgenic mice through antiangiogenic and non-antiangiogenic mechanisms

Cancer growth and progression is often critically influenced by the production of vascular endothelial growth factor (VEGF), a key mediator of angiogenesis. VEGF produced by tumor cells stimulates endothelial cell growth through the binding and activation of the KDR/Flk-1 receptor (VEGFR-2) on endothelial cells. Recently, some human breast cancer epithelial cells have been shown to express VEGF receptors, suggesting a potential autocrine-mediated growth stimulation of a subset of cancers by VEGF. We demonstrate that mammary tumors in the C3(1)/Tag transgenic model express VEGF and VEGF receptors and tumor growth is stimulated by this autocrine mechanism. GW654652, an indazolylpyrimidine, is a VEGFRs tyrosine kinase inhibitor that dramatically reduces both angiogenesis and tumor cell growth in this model, as demonstrated using both in vitro and in vivo assays. GW654652 significantly decreased cell proliferation and induced apoptosis in human umbilical vein endothelial cells and M6 mammary tumor cells derived from C3(1)/Tag (Tag: simian virus 40 T-antigen) transgenic mice. A 75% reduction in VEGF-induced angiogenesis was observed with GW654652 using the chick chorioallantoic membrane assay, whereas GW654652 produced an approximately 85% reduction in angiogenesis as assessed by the Matrigel plug assay. A profound inhibitory effect on tumor growth in the C3(1)/Tag transgenic model of human breast cancer was observed with oral administration of GW654652 as measured by delayed tumor onset, decreased multiplicity, reduced tumor volume, and extended animal survival. The antitumor effects of GW654652 were associated with reduced tumor vascularization and no apparent toxicity. Tumor growth, however, rapidly advanced following cessation of treatment. This is the first demonstration that a VEGF receptor inhibitor, GW654652, has a strong inhibitory effect on angiogenesis and tumor progression in a transgenic model of mammary cancer, suggesting that this is a useful approach for preclinical testing of such agents.     

The Prognostic Significance of Vascular Endothelial Growth Factor (VEGF C-1) Immunoexpression in Oligodendroglioma. An Analysis of 91 Cases

Oligodendrogliomas continue to generate considerable difficulties in identifying prognostic factors, including single histopathological patterns. Among the latter, vascular productive changes have been intensively examined but the obtained results appear to be controversial. Numerous studies have revealed an indisputable importance of vascular endothelial growth factor (VEGF) immunoreactivity for malignant progression of astrocytomas but the data regarding oligodendrogliomas are heterogeneous. Ninety-one patients with oligodendroglioma were examined retrospectively for VECF immunoexpression. The results demonstrated significant preponderance of intracellular VEGF expression for WHO grade III tumors. Nevertheless, VEGF staining patterns correlated with both progression-free and overall survival only in univariate, but not in multivarite analysis. Only WHO tumor grade was found to be an independent prognostic factor for oligodendroglioma outcome. Therefore, it seems unlikely that VEGF immunohistochemistry will be of value in assessing individual oligodendroglioma prognosis, especially for determining of both progression-free and overall survival from histologically low-grade tumors.     

Overexpression of vascular endothelial growth factor isoforms drives oxygenation and growth but not progression to glioblastoma multiforme in a human model of gliomagenesis

Vascular endothelial growth factor (VEGF) is thought to promote tumor growth and angiogenesis. Whereas VEGF is up-regulated in only a portion of anaplastic astrocytoma (AA), it is overexpressed in most glioblastoma multiforme (GBM), and the level of expression is correlated with grade of glioma. To explore the possibility that VEGF may act as a driving force in the progression of AA to GBM, the VEGF isoforms VEGF(121) and VEGF(165) were overexpressed in genetically modified, mutant H-Ras-transformed human astrocytes that on intracranial implantation form AA-like tumors. The ability of the VEGF isoforms to stimulate growth, angiogenesis, oxygenation, and the formation of necrotic GBM-like tumors was then monitored. The parental mutant H-Ras-modified astrocytes expressed four times more endogenous VEGF than normal human astrocytes, but on intracranial implantation formed hypovascular, hypoxic, small AA-like tumors. Whereas these modest levels of VEGF overexpression were insufficient to drive oxygenation and GBM formation, an additional 8-fold increase in VEGF expression mediated by retroviral infection with constructs encoding either VEGF (121) or VEGF (165) resulted in cells which, after intracranial implantation, formed tumors that were larger, more vascular, and better oxygenated than those formed by the mutant H-ras parental cells. However, the tumors formed by the cells expressing exogenous VEGF (121) or VEGF (165) retained the phenotype of AA, lacking areas of necrosis that are the hallmark of the GBM phenotype. These results suggest that whereas the VEGF(121) and VEGF(165) isoforms can contribute to glioma vascularization, oxygenation, and growth, they do not in and of themselves drive the formation of the GBM phenotype.     

Microvessel density, VEGF expression, and tumor-associated macrophages in breast tumors: correlations with prognostic parameters

Angiogenesis plays an important role in tumor growth, metastasis, and prognosis. Vascular endothelial growth factor (VEGF) is a potent endothelial mitogen and acts on the angiogenic stimulation of human neoplasias. In infiltrative ductal carcinoma (IDC), VEGF expression is correlated with high vascularity. Tumor-associated macrophages (TAMs) contribute to tumor proliferation, progression and angiogenesis and have a complex role in tumor biology. In this study, the correlations between microvessel density (MVD), VEGF expression, and TAMs and their relations to clinicopathological parameters such as tumor size, metastatic lymph node, mitotic activity index (MAI) and tumor grade were investigated in 48 cases of IDC and 30 infiltrative lobular carcinoma (ILC) cases. MVD showed a significant positive correlation with TAMs, VEGF, metastatic lymph nodes, tumor size and grade in IDC (P < 0.001). In ILC, MVD and tumor size were positively correlated (P = 0.003), while MVD was not correlated with VEGF, TAMs, MAI, metastatic lymph nodes, and grade. These findings are suggestive of angiogenesis stimulation in IDCs by VEGF, driving the macrophages into the tumor area. MVD and TAMs were found to be important prognostic factors in IDCs. On the other hand, however, VEGF did not contribute to angiogenesis in ILCs, and MVD and TAMs did not have any prognostic significance. These results suggest the involvement of factors not related to VEGF in the angiogenesis of lobular carcinoma.     

Sunitinib but not VEGF blockade inhibits cancer stem cell endothelial differentiation

Different mechanisms of angiogenesis and vasculogenesis are involved in the development of the tumor vasculature. Among them, cancer stem cells are known to contribute to tumor vasculogenesis through their direct endothelial differentiation. Here, we investigated the effect of anti-angiogenic therapy on vasculogenesis of cancer stem cells derived from breast and renal carcinomas. We found that all the anti-angiogenic approaches impaired proliferation and survival of cancer stem cells once differentiated into endothelial cells in vitro and reduced murine angiogenesis in vivo. At variance, only VEGF-receptor inhibition using the non-specific tyrosine kinase inhibitor Sunitinib or the anti-VEGF-receptor 2 neutralizing antibody, but not VEGF blockade using Bevacizumab, impaired the process of endothelial differentiation in vitro, suggesting a VEGF-independent mechanism. In addition, tyrosine kinase inhibition by Sunitinib but not VEGF blockade using the soluble VEGF trap sFlk1 inhibited the cancer stem cell-induced vasculogenesis in vivo. Accordingly, Sunitinib but not Bevacizumab inhibited the induction of hypoxia-inducible factor pathway occurring during endothelial differentiation under hypoxia. The present results highlight a differential effect of VEGF-receptor blockade versus VEGF inhibition in tumor vascularization. VEGFR blockade inhibits the process of tumor vasculogenesis occurring during tumor hypoxia whereas the effect of VEGF inhibition appears restricted to differentiated endothelial cells.     

Tumor angiogenesis in breast cancer: Its importance as a prognostic indicator and the association with vascular endothelial growth factor expression

Summary The importance of tumor angiogenesis in the process of tumor growth and progression in solid tumors has been widely accepted. We have investigated the significance of tumor angiogenesis as a prognostic indicator in a retrospective study including 328 primary breast cancer patients. The postoperative survey demonstrated that the microvessel density (MVD) evaluated by immunocytochemical staining for factor VIII-related antigen is a potent prognostic indicator. The relapse-free survival (RFS) rate of patients with over 100 microvessels/mm² in a microscopic field was significantly worse compared to that of patients with less than 100 microvessels/mm² (p<0.00001). The significance of MVD was found in both node-negative and node-positve patients (p< 0.005 and p<0.01, respectively). Multivariate analysis confirmed that MVD is an independent prognostic indicator for RFS. In the background factor analysis, MVD was significantly correlated with the number of metastatic nodes (p<0.01). In addition, the immunocytochemical analysis for vascular endothelial growth factor (VEGF) demonstrated a close association between the increase in MVD and the expression of VEGF (p<0.001). VEGF status also was a significant prognostic indicator in univariate analysis for RFS (p<0.01). It was concluded that MVD is a potent prognostic indicator in primary breast cancer. Furthermore, it was also suggested that VEGF plays crucial roles in the promotion of angiogenesis in breast cancer.Abbreviations MVD microvessel density - VEGF vascular endothelial growth factor     

Plasma vascular endothelial growth factor is useful in assessing progression of breast cancer post surgery and during adjuvant treatment

Vascular endothelial growth factor (VEGF) has been shown to induce angiogenesis in vivo and in vitro. However, the association of plasma VEGF with tumor histopathology in high risk groups such as African American and non-white Hispanic women with breast cancer is not well understood. There is limited information on the prognostic relevance of plasma VEGF in patients who have had surgery and adjuvant treatment for breast cancer. In this study, we measured plasma VEGF from 125 minority women with primary breast tumor removal and were completing adjuvant treatment. The control group consisted of 20 subjects without cancer. We examined the association between plasma VEGF and other tumor characteristics such as steroid hormone receptors, tumor size, regional nodes, stage, recurrence, and overall survival. Our results confirmed that plasma VEGF levels were significantly higher in breast cancer patients than normal subjects. Plasma VEGF level increased in patients with increase in tumor size, and at late stage III/IV disease. Univariate analysis showed plasma VEGF to be a significant predictor of overall survival (RR=2.5, p=0.02). Multivariate analysis showed plasma VEGF not only to be an independent predictor of overall survival (RR=4.6, p=0.02) but also of local recurrence (RR=6.0, p=0.04). Tamoxifen in combination with CMF or CAF can reduce plasma VEGF level in patients with estrogen receptor positive tumor but not in estrogen receptor negative tumor. Our findings suggest that plasma VEGF should be considered as a tumor marker for breast cancer progression, and inhibitors of angiogenesis should be factored into the treatment protocol for patients who demonstrate increase in plasma VEGF levels at any stage of the disease.     

A comparative survival evaluation and assessment of interclassification concordance in adult supratentorial astrocytic tumors

Classification and grading of astrocytic tumors has been the subject of several controversies and no universally accepted classification system is yet available. Nevertheless, acceptance of a common system is important for assessing prognosis as well as easy comparative evaluation and interpretation of the results of multi-center therapeutic trials. We report the results of a single center study on comparative survival evaluation along with assessment of inter-classification concordance in 102 cases of supratentorial astrocytic tumors in adults ((3) (3)16 years of age). Hematoxylin and eosin (H&E) stained slides of these 102 cases were reviewed independently by two pathologists and each case classified or graded according to four different classification systems viz. Kernohan, Daumas-Duport (SAM-A), TESTAST-268 and WHO. The histological grading was then correlated with the survival curves as estimated by the Kaplan-Meier method. The most important observation was that similar survival curves were obtained for any one grade of tumor by all the four classification systems. Fifty three of the 102 cases (51.9%) showed absolute grading concordance using all 4 classifications with maximum concordant cases belonging to grades 2 and 4. Intra-classification grade-wise survival analysis revealed a statistically significant difference between grade 2 and grades 3 or 4, but no difference between grades 3 and 4 in any of the classification systems. It is apparent from the results of this study that if specified criteria related to any of the classification systems is rigorously adhered to, it will produce comparable results. Hence, preferential adoption of any one classification system in practice will be guided by the relative ease of histologic feature value evaluation with maximum possible objectivity and reproducibility. We recommend the Daumas-Duport (SAM-A) system since it appears to be the simplest, most objectivized for practical application and highly reproducible with relative ease.     

Embryonic Protein Nodal Promotes Breast Cancer Vascularization

Tumor vascularization is requisite for breast cancer progression, and high microvascular density in tumors is a poor prognostic indicator. Patients bearing breast cancers expressing human embryonic stem cell (hESC)-associated genes similarly exhibit high mortality rates, and the expression of embryonic proteins is associated with tumor progression. Here, we show that Nodal, a hESC-associated protein, promotes breast cancer vascularization. We show that high levels of Nodal are positively correlated with high vascular densities in human breast lesions (P = 0.0078). In vitro, we show that Nodal facilitates breast cancer-induced endothelial cell migration and tube formation, largely by upregulating the expression and secretion of proangiogenic factors by breast cancer cells. Using a directed in vivo angiogenesis assay and a chick chorioallantoic membrane assay, we show that Nodal promotes vascular recruitment in vivo. In a clinically relevant in vivo model, whereby Nodal expression was inhibited following tumor formation, we found a significant reduction in tumor vascularization concomitant with elevated hypoxia and tumor necrosis. These findings establish Nodal as a potential target for the treatment of breast cancer angiogenesis and progression. Cancer Res; 72(15); 3851-63. ?2012 AACR.     

Proposal of a scoring scale as a survival predictor in intracranial oligodendrogliomas

SummaryIntroduction Histological, clinical and radiological features, and molecular genetic analysis are among the factors that have been considered in defining the prognosis of oligodendrogliomas (OD), but they have yielded conflicting results.The purpose of this study was to test out a scoring scale based on clinical, radiological, pathological and molecular features.Material and method To identify factors with prognostic significance, we analyzed 87 treated patients with a histological diagnosis of OD. Of the parameters analyzed, age, onset, clinical status, radiological enhancement, histological necrosis, mitosis and chromosomal anomalies emerged as significant prognosis factors using univariate analysis. Multivariate analysis revealed age and chromosomal anomalies as independent factors of survival.Results The factors with a significant prognostic value were combined to determine which grouping factors best predict outcome. The proposed score is a pure number resulting from a combination of: 2 major factors: age and chromosomal anomalies (scored 3–0); 5 minor factors: onset, clinical examination, necrosis, mitoses (scored 1–0), and radiological enhancement (scored 2–0). According to our scale, 10 survival curves were produced for overall survival. Recursive partitioning of patients with the nearest score and outcome produced four groups with a significant difference in survival (p=10⁻⁵). The power of both the scale and the partitioned groups for predicting outcome was more accurate than the WHO and St Anne grading systems, and the molecular sub-classification.Conclusions Our scale is a plausible way of classifying patients harboring intracranial OD according to expected survival.     

KDR activation in astrocytic neoplasms.

BACKGROUND: The development of new capillary networks appears to be necessary for the growth of solid tumors. Tumor angiogenesis is believed to be mediated by soluble factors released from tumor cells that then act on endothelial cells in a paracrine manner. Vascular endothelial growth factor (VEGF) is a prime regulator of normal and tumor angiogenesis as well as vasculogenesis. VEGF is expressed in glioma cells and its receptors (Flt-1 and KDR) are expressed in the same gliomas. The two receptors are tyrosine kinases and have an extracellular domain containing seven immunoglobulin-like loops and a split tyrosine-kinase domain. KDR is a receptor for the various VEGF isoforms and for VEGF-C; Flt-1 is a receptor for the various isoforms. Studies suggest that the VEGF receptors are induced in endothelial cells during tumor angiogenesis. Stimulation of aortic endothelial cells results in receptor tyrosine phosphorylation (receptor activation). In this study the activation state of the KDR receptors was determined in low grade, anaplastic, and high grade gliomas. METHODS: A synthetic tyrosine phosphopeptide was used to raise an antibody that recognizes the phosphorylation state of tyrosine 1054/1059 in the KDR receptor. Western blot analysis was performed on 37 astrocytic neoplasms (7 low grade astrocytomas, 13 anaplastic astrocytomas, and 17 cases of glioblastoma multiforme). RESULTS: Immunoblotting with this antibody found that tyrosines 1054/1059 were phosphorylated constitutively within multiple fresh surgical specimens of glioblastomas (71%) and anaplastic gliomas (15%), but not in low grade gliomas. CONCLUSIONS: The findings of the current study strongly support the hypothesis that the onset of angiogenesis is an important event during the disease progression of gliomas.     

Patterns of angiogenesis in nonsmall-cell lung carcinoma

BACKGROUND: Tumor angiogenesis plays a pivotal role in tumor growth, maintenance, and metastasis. The objective of the current study was to evaluate the prognostic value of estimates of tumor angiogenesis and vascular endothelial growth factor (VEGF) status in 143 primary tumors from patients who underwent radical surgery for nonsmall-cell lung carcinoma (NSCLC). METHODS: Tumor sections were stained by immunohistochemistry for CD34 and VEGF. Angiogenesis was estimated both by a modification of the method described by Weidner and by the use of a 25-point Chalkley eyepiece graticule. VEGF intensity was evaluated semiquantitatively in three groups of patients. The vascular data were correlated with histopathologic tumor type and grade, TNM classification, patient age, and the endpoint (death). RESULTS: The estimates of vascular score did not reveal any prognostic information. In 35 patients (24%), invasive tumor growth was identified with a highly ordered alveolar microvessel pattern. In parallel sections, the intensity of VEGF staining was weak in tumors that exhibited an alveolar microvessel pattern only, and it was more intense in tumors that demonstrated a mixed alveolar and diffuse angiogenic pattern. The 35 patients with alveolar microvessel pattern had a significantly better survival (P = 0.007). In a Cox multivariate analysis, the results demonstrated an independent bad prognostic value of high disease stage (P < 0.0001), adenocarcinoma (P = 0.004), greater age (P = 0.01), and angiogenic microvessel pattern (P = 0.01). CONCLUSIONS: The authors believe that the alveolar vascular pattern represented preexisting alveolar vessels, that is, the alveoli were filled up by tumor cells that exploited the existing highly vascular bed of the lungs. Therefore, this subgroup was characterized by tumor progression without the induction of angiogenesis. The current data do not support a significant prognostic role for tumor angiogenesis in patients who are diagnosed with NSCLC. This may have implications for therapy aimed at inhibiting tumor growth by the inhibition of angiogenesis.     

环氧合酶-2对鼻咽癌血管生成及预后的影响

目的研究环氧合酶-2(COX-2)在鼻咽癌中的表达及其对血管生成及预后的影响.方法选取临床资料完整并随访达5年以上的86例鼻咽癌患者,采用免疫组织化学技术检测活检标本中COX-2、血管内皮生长因子(VEGF)表达和微血管密度(MVD).结果 COX-2在鼻咽癌组织中阳性表达率为73.3%(63/86),与VEGF表达[69.8%(60/86)]呈显著正相关(rs=0.438,P<0.01),且与肿瘤分级、原发灶范围、颈淋巴结转移、远地转移及较短生存期亦具相关性.MVD平均数为32.3±12.8.结论 COX-2在鼻咽癌组织中高表达,与肿瘤血管生成密切相关,可作为预测鼻咽癌预后的一种有用指标.     

Significance of vascular endothelial growth factor in growth and peritoneal dissemination of ovarian cancer

Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis which drives endothelial cell survival, proliferation, and migration while increasing vascular permeability. Playing an important role in the physiology of normal ovaries, VEGF has also been implicated in the pathogenesis of ovarian cancer. Essentially by promoting tumor angiogenesis and enhancing vascular permeability, VEGF contributes to the development of peritoneal carcinomatosis associated with malignant ascites formation, the characteristic feature of advanced ovarian cancer at diagnosis. In both experimental and clinical studies, VEGF levels have been inversely correlated with survival. Moreover, VEGF inhibition has been shown to inhibit tumor growth and ascites production and to suppress tumor invasion and metastasis. These findings have laid the basis for the clinical evaluation of agents targeting VEGF signaling pathway in patients with ovarian cancer. In this review, we will focus on VEGF involvement in the pathophysiology of ovarian cancer and its contribution to the disease progression and dissemination.     

The antitumor and antiangiogenic activity of vascular endothelial growth factor receptor inhibition is potentiated by ErbB1 blockade.

PURPOSE: Receptor tyrosine kinases of the ErbB family play important roles in the control of tumor growth. Vascular endothelial growth factor (VEGF) stimulates endothelial cell proliferation, enhances vascular permeability, and plays an important role in tumor vascularization. We evaluated the effects of selective VEGF receptor (VEGFR; PTK787/ZK222584) and ErbB (PKI166 and ZD1839) inhibitors on tumor growth and angiogenesis and asked whether additional therapeutic benefit was conferred by combination treatment. EXPERIMENTAL DESIGN: The antitumor activity of each inhibitor alone or in combination was assessed in human cancer models in immunocompromised mice. ErbB receptor expression and activation of downstream signaling pathway was evaluated in both tumor and endothelial cells. RESULTS: Both ErbB inhibitors significantly enhanced the antitumor activity of PTK787/ZK222584. In vitro, ErbB1 inhibition blocked VEGF release by tumor cells and proliferation of both tumor and endothelial cells. In an in vitro angiogenesis assay, epidermal growth factor (EGF) stimulated the release of VEGF by smooth muscle cells resulting in increased angiogenesis, a response blocked by administration of PTK787/ZK222584. Under basal condition, both ZD1839 and PTK787/ZK222584 blocked sprouting, likely via inhibition of an autocrine ErbB1 loop and VEGFR signaling, respectively, in endothelial cells. In conditions of limiting VEGF, EGF plays an important role in endothelial cell proliferation, survival, and sprouting. CONCLUSION: We have shown that activation of ErbB1 triggers a plethora of effects, including direct effects on tumor and endothelial cells and indirect effects mediated via induction of VEGF release. Simultaneous blockade of ErbB1 and VEGFR pathways results in a cooperative antitumor effect, indicating that this combination may represent a valid therapeutic strategy.