Vascular endothelial growth factor and prognosis in patients with node-negative breast cancer

G-quadruplexes in cancer-related gene promoters: from identification to therapeutic targeting

INTRODUCTION

Guanine-rich DNA sequences can fold into four-stranded noncanonical secondary structures called G-quadruplexes (G4s) which are widely distributed in functional regions of the human genome, such as telomeres and gene promoter regions. Compelling evidence suggests their involvement in key genome functions such as gene expression and genome stability. Notably, the abundance of G4-forming sequences near transcription start sites suggests their potential involvement in regulating oncogenes.

AREAS COVERED

This review provides an overview of current knowledge on G4s in human oncogene promoters. The most representative G4-binding ligands have also been documented. The objective of this work is to present a comprehensive overview of the most promising targets for the development of novel and highly specific anticancer drugs capable of selectively impacting the expression of individual or a limited number of genes.

EXPERT OPINION

Modulation of G4 formation by specific ligands has been proposed as a powerful new tool to treat cancer through the control of oncogene expression. Actually, most of G4-binding small molecules seem to simultaneously target a range of gene promoter G4s, potentially influencing several critical driver genes in cancer, thus producing significant therapeutic benefits.

Vascular Endothelial Growth Factor Receptors [VEGFR] as Target in Breast Cancer Treatment: Current Status in Preclinical and Clinical Studies and Future Directions

Breast cancer [BC] is one of the most common cancers among women, one of the leading causes of a considerable number of cancer-related death globally. Among all procedures leading to the formation of breast tumors, angiogenesis has an important role in cancer progression and outcomes. Therefore, various anti-angiogenic strategies have developed so far to enhance treatment's efficacy in different types of BC. Vascular endothelial growth factors [VEGFs] and their receptors are regarded as the most well-known regulators of neovascularization. VEGF binding to vascular endothelial growth factor receptors [VEGFRs] provides cell proliferation and vascular tissue formation by the subsequent tyrosine kinase pathway. VEGF/VEGFR axis displays an attractive target for anti-angiogenesis and anti-cancer drug design. This review aims to describe the existing literature regarding VEGFR inhibitors, focusing on BC treatment reported in the last two decades.

Signaling pathways modulated by miRNAs in breast cancer angiogenesis and new therapeutics

MicroRNAs (miRNAs) act as oncogenes or tumor suppressors by suppressing the expression of target genes, some of which are engaged in angiogenic signaling pathways directly or indirectly. Tumor development and metastasis are dependent on angiogenesis, and it is the main reason for the poor prognosis of cancer patients. New blood vessels are formed from pre-existing vessels when angiogenesis occurs. Thus, it is essential to develop primary tumors and the spread of cancer to surrounding tissues. MicroRNAs (miRNAs) are small noncoding RNAs involved in various biological processes. They can bind to the 3'-UTR of their target genes and prevent them from expressing. MiRNAs control the activity of endothelial cells (ECs) through altering many biological pathways, which plays a key role in cancer progression and angiogenesis. Recent findings revealed that tumor-derived extracellular vesicles participated directly in the control of tumor angiogenesis by delivering miRNAs to ECs. miRNAs recently show great promise in cancer therapies to inhibit angiogenesis. In this study, we showed the miRNA-regulated signaling pathways in tumor angiogenesis with highlighting the anti-angiogenic therapy response and miRNA delivery methods that have been used to inhibit angiogenesis in both in vivo and in vitro studies.

Associations of angiogenesis-related proteins with specific prognostic factors, breast cancer subtypes and survival outcome in early-stage breast cancer patients. A Hellenic Cooperative Oncology Group (HeCOG) trial

Several studies support an important role of angiogenesis in breast cancer growth and metastasis. The main objectives of the study were to investigate the immunohistochemical expression of vascular endothelial growth factor (VEGF) family ligands (VEGF-A and VEGF-C) and receptors (VEGFR1, VEGFR2 and VEGFR3) in breast cancer and their associations with clinicopathological parameters, cancer subtypes/subgroups and patient outcome. Formalin-fixed paraffin-embedded tumor tissue samples were collected from early-stage breast cancer patients treated with anthracycline-based chemotherapy within a randomized trial. Immunohistochemistry was performed on serial 2.5 μm thick tissue sections from tissue microarray blocks. High VEGF-A, VEGF-C, VEGFR1, VEGFR2 and VEGFR3 protein expression was observed in 11.8% (N = 87), 80.8% (N = 585), 28.1% (N = 202), 64.6% (N = 359) and 71.8% (N = 517) of the cases, respectively. Significant associations were observed among all proteins (all p-values <0.05), with the exception of the one between VEGF-C and VEGFR1 (chi-square test, p = 0.15). Tumors with high VEGF-A protein expression, as compared to tumors with low expression were more frequently ER/PgR-negative (33.3% vs. 20.8%, chi-square test, p = 0.009) and HER2-positive (44.8% vs. 20.6%, p<0.001). In addition, tumors with high VEGFR1 expression, were more frequently HER2-positive (32.8% vs. 19.6%, p<0.001), while tumors with high VEGFR3 expression were more frequently ER/PgR-negative (24.9% vs. 17.0%, p = 0.024) and HER2-positive (26.9% vs. 14.8%, p = 0.001). High VEGF-A and VEGF-C protein expression was associated with increased DFS in the entire cohort (HR = 0.57, 95% CI 0.36–0.92, Wald’s p = 0.020 and HR = 0.71, 95% CI 0.52–0.96, p = 0.025, respectively), as well as in specific subtypes/subgroups, such as HER2-positive (VEGF-A, HR = 0.32, 95% CI 0.14–0.74, p = 0.008) and triple-negative (VEGF-C, HR = 0.44, 95% CI 0.21–0.91, p = 0.027) patients. High vs. low VEGFR1 expression was an unfavorable factor for DFS in triple-negative patients (HR = 2.74, 95% CI 1.26–5.98, p = 0.011), whereas the opposite was observed among the ER/PgR-positive patients (HR = 0.69, 95% CI 0.48–0.98, p = 0.041). Regarding OS, high VEGF-C protein expression was associated with increased OS in the entire cohort (HR = 0.64, 95% CI 0.46–0.89, Wald’s p = 0.008), as well as in in specific subtypes/subgroups, such as ER/PgR-negative (HR = 0.37, 95% CI 0.20–0.71, p = 0.003) and triple-negative (HR = 0.42, 95% CI 0.19–0.90, p = 0.026) patients. In conclusion, high expression of angiogenesis-related proteins is associated with adverse clinicopathological parameters in early-stage breast cancer patients and may be surrogate markers of biologically distinct subgroups of ER/PgR-negative or triple-negative tumors with superior outcome. Further validation of our findings in independent cohorts is needed.

Epigenetic regulation of vascular endothelial growth factor a dynamic expression in transitional cell carcinoma

Vascular endothelial growth factor A (VEGF-A) is a key mediator in the neovascularization of cancers. We have found that VEGF-A was expressed at significantly higher levels in high-grade transitional cell carcinoma (TCC) cells than low-grade TCC cells in our previous study. In the present study, promoter methylation pattern was assessed and quantified by bisulfite genomic sequencing (BGS) and specific VEGF-A CpG sites in low-grade, but not in high-grade, TCC cells were observed. Reporter assays indicated that hypermethylation of nine CpG sites can inhibit the transcriptional activity of the VEGF-A gene. Subsequent chromatin immunoprecipitation (ChIP) assay revealed down-regulation of transcription activity of VEGF-A with increasing binding of methyl-CpG-binding protein 2 (MBD2) and trimethyl-histone H3 (Lys9) proteins to these CpG sites in low-grade TCC cells during hypermethylation. Furthermore, treatment of low-grade TCC cells with DNA methyltransferase inhibitor and histone deacetylase inhibitor can restore the expression of VEGF-A and promote the invasive ability of low-grade TCC cells. Hypermethylation with lower expression levels of VEGF-A in low-grade TCC tumors than high-grade TCC tumors was also confirmed in clinical specimens by reverse transcriptase-PCR and pyrosequencing analyses. Our findings are the first results indicating that VEGF-A expression is suppressed in low-grade TCC tumors by promoter hypermethylation. This offers a new perspective on the role of VEGF-A in TCC tumor behavior.

Breast Tumor Angiogenesis and Tumor-Associated Macrophages: Histopathologist's Perspective

Much progress has been made since the conceptualization of tumor angiogenesis—the induction of growth of new blood vessels by tumor—as a salient feature of clinically significant primary or metastatic cancers. From a practicing histopathologist's point of view, we appraise the application of this concept in breast cancer with particular reference to the evaluation of proangiogenic factors and the assessment of new microvessels in histopathological examination. Recently, much focus has also been centered on the active roles played by tumor-associated macrophages in relation to tumor angiogenesis. We review the literature; many data supporting this facet of tumor angiogenesis were derived from the breast cancer models. We scrutinize the large body of clinical evidence exploring the link between the tumor-associated macrophages and breast tumor angiogenesis and discuss particularly the methodology and limitations of incorporating such an assessment in histopathological examination.

The association between vascular endothelial growth factor expression in invasive breast cancer and survival varies with intrinsic subtypes and use of adjuvant systemic therapy: results from the Nurses' Health Study

Vascular endothelial growth factor (VEGF) is important in breast carcinogenesis. However, whether the effect of VEGF expression on survival varies with intrinsic subtypes of breast cancer remains unclear and the prognostic significance of VEGF expression in breast cancer remains controversial. Using immunostaining of tissue microarray sections, VEGF expression was determined in 1,788 primary invasive breast cancers identified from the Nurses' Health Study cohort. Cox proportional hazards models were used to estimate hazard ratios (HR) of breast cancer-specific and overall mortality and distant recurrence, adjusted for epidemiological, clinicopathological, and related molecular factors, and year of diagnosis. Overall, 72.5% of breast cancers were positive for VEGF. VEGF expression was correlated with intrinsic subtypes (P < 0.0001), with higher frequency in luminal B, HER2, and basal-like types versus luminal A type. Although VEGF expression was not significantly related to worse survival when all cases were considered together, it was significantly associated with increased risks for breast cancer-specific mortality (BCSM) (HR = 1.41, 95% CI = 1.01, 1.97) and distant recurrence (HR = 1.49, 95% CI = 1.07, 2.07) among women with luminal A tumors. In 262 women untreated systemically, VEGF expression was significantly associated with BCSM (HR = 5.58, 95% CI = 1.17, 26.66). In 902 women receiving adjuvant hormonal therapy, VEGF expression did not significantly predict clinical outcomes. The VEGF-associated increased risk of BCSM is limited to luminal A tumors. VEGF expression is a prognostic but not predictive marker of hormonal response in non-metastatic invasive breast cancer.

Correlation between hepatocyte growth factor receptor and vascular endothelial growth factor-A in breast carcinoma

The aim of the study was to evaluate the prognostic value of the vascular endothelial growth factor A (VEGF-A) and hepatocyte growth factor receptor (HGFR, c-met) expressions in homogenous group of breast cancer patients. Tumor samples were collected from 98 patients with invasive ductal breast carcinoma stage II treated with primary surgery. We have observed a strong correlation between VEGF-A and c-met. No correlations were found between VEGF-A or HGFR expressions and clinical parameters (tumor size, grade, axillary lymph node status, age), 5- and 10-years DFS or OS. Our study did not reveal any prognostic value of c-met or VEGF. In addition they are not useful to separate a patients' subgroup with poor prognosis. Unlike in other authors' studies, our patients' group is very homogenous which might tribute to obtained results.

Circulating and imaging markers for angiogenesis

Abundant preclinical and indirect clinical data have for several decades convincingly supported the notion that anti-angiogenesis is an effective strategy for the inhibition of tumor growth. The recent success achieved in patients with metastatic colon carcinoma using a neutralizing antibody directed against vascular endothelial growth factor (VEGF) has translated preclinical optimism into a clinical reality.With this transformation in the field of angiogenesis has come a need for reliable surrogate markers. A surrogate marker by definition serves as a substitute for the underlying process in question, and in the case of angiogenesis, microvessel density (usually in so-called "hot-spots") has until now been the most widely used parameter. However, this parameter is more akin to a static "snap-shot" and does not lend itself either to the dynamic in situ assessment of the status of the tumor microvasculature or to the molecular factors that regulate its growth and involution. This has led to an acute need for developing circulating and imaging markers of angiogenesis that can be monitored in vivo at repeated intervals in large number of patients with a variety of tumors in a non-invasive manner. Such markers of angiogenesis are the subject of this review.

Clinical biomarkers for hypoxia targeting

Tumor hypoxia or a reduction of the tissue oxygen tension is a key microenvironmental factor for tumor progression and treatment resistance in solid tumors. Because hypoxic tumor cells have been demonstrated to be more resistant to ionizing radiation, hypoxia has been a focus of laboratory and clinical research in radiation therapy for many decades. It is believed that proper detection of hypoxic regions would guide treatment options and ultimately improve tumor response. To date, most clinical efforts in targeting tumor hypoxia have yielded equivocal results due to the lack of appropriate patient selection. However, with improved understanding of the molecular pathways regulated by hypoxia and the discovery of novel hypoxia markers, the prospect of targeting hypoxia has become more tangible. This chapter will focus on the development of clinical biomarkers for hypoxia targeting.

Vascular endothelial growth factor is a strong predictor of early distant recurrences in a prospective study of premenopausal women with lymph-node negative breast cancer

We investigate the prognostic significance of the pro-angiogenic cytokine vascular endothelial growth factor (VEGF), urokinase-type plasminogen activator (uPA), plasminogen activator inhibitor 1 (PAI-1), and S-phase fraction (SPF) for distant disease free survival (DDFS) in 219 premenopausal patients with node-negative breast cancer (NNBC). In univariate analysis significantly shorter DDFS was observed for patients with high VEGF (p=0.006), high uPA (p=0.001), and high SPF (p<0.001). The prognostic significance of VEGF varied over time being very strong for early relapses (0-2.25 years follow-up) (HR=7.9; p=0.006) while no difference was seen in the subsequent follow-up period (HR=1.3; p=0.62). In a series of bivariate analyses VEGF provided prognostic information during the whole observation period (0-72 months) in addition to age, tumour size, oestrogen receptor (ER), progesterone receptor (PgR), and uPA. Also this effect was more pronounced during the first follow-up period suggesting VEGF as a marker of early recurrences.

Identification of VEGF-regulated genes associated with increased lung metastatic potential: functional involvement of tenascin-C in tumor growth and lung metastasis

Metastasis is the primary cause of death in patients with breast cancer. Overexpression of c-myc in humans correlates with metastases, but transgenic mice only show low rates of micrometastases. We have generated transgenic mice that overexpress both c-myc and vascular endothelial growth factor (VEGF) (Myc/VEGF) in the mammary gland, which develop high rates of pulmonary macrometastases. Gene expression profiling revealed a set of deregulated genes in Myc/VEGF tumors compared to Myc tumors associated with the increased metastatic phenotype. Cross-comparisons between this set of genes with a human breast cancer lung metastasis gene signature identified five common targets: tenascin-C(TNC), matrix metalloprotease-2, collagen-6-A1, mannosidase-alpha-1A and HLA-DPA1. Signaling blockade or knockdown of TNC in MDA-MB-435 cells resulted in a significant impairment of cell migration and anchorage-independent cell proliferation. Mice injected with clonal MDA-MB-435 cells with reduced expression of TNC demonstrated a significant decrease (P<0.05) in (1) primary tumor growth; (2) tumor relapse after surgical removal of the primary tumor and (3) incidence of lung metastasis. Our results demonstrate that VEGF induces complex alterations in tissue architecture and gene expression. The TNC signaling pathway plays an important role in mammary tumor growth and metastases, suggesting that TNC may be a relevant target for therapy against metastatic breast cancer.

The potential role of intrinsic hypoxia markers as prognostic variables in cancer

Tumor hypoxia is related to tumor progression and therapy resistance, which leads to poor patient outcome. It has been suggested that measuring the hypoxic status of a tumor helps to predict patient outcome and to select more targeted treatment. However, current methods using needle electrodes or exogenous markers have limitations due to their invasiveness or necessity for preinjection. Recent studies showed that hypoxia-regulated genes could be alternatively used as endogenous hypoxia markers. This is a review of 15 hypoxia-regulated genes, including hypoxia-inducible factor-1 and its targets, and their correlation with tumor hypoxia and patient outcome from 213 studies. Though most of the studies showed significance of these genes in predicting prognosis, there was no definitive prognostic and hypoxia marker. In conclusion, this review suggests the need for further studies with standardized methods to examine gene expression, as well as the use of multiple gene expressions.

The role of copper in tumour angiogenesis

Copper stimulates the proliferation and migration of endothelial cells and is required for the secretion of several angiogenic factors by tumour cells. Copper chelation decreases the secretion of many of these factors. Serum copper levels are upregulated in many human tumours and correlate with tumour burden and prognosis. Copper chelators reduce tumour growth and microvascular density in animal models. New orally active copper chelators have enabled clinical trials to be undertaken, and there are several studies ongoing. A unifying mechanism of action by which copper chelation inhibits endothelial cell proliferation and tumour secretion of angiogenic factors remains to be elucidated, but possible targets include copper-dependent enzymes, chaperones, and transporters.

Expression of vascular endothelial growth factor and proliferation marker MIB1 are influenced by neoadjuvant chemotherapy in locally advanced breast cancer

Neoadjuvant chemotherapy (NACT) has become the standard of care for patients with locally advanced breast cancer (LABC). This was a retrospective review of 21 consecutive women who received NACT as initial treatment of LABC, followed by surgical excision. The pre- and post-treatment breast specimens and post-treatment axillary lymph nodes with metastases were immunostained to evaluate for proliferative index (PI) (MIB-1 Immunotech) and vascular endothelial growth factor (VEGF) expression (Santa Cruz, CA, clone A-20). Thirteen of the 21 patients (62%) had more than 50% tumor shrinkage following NACT. The breast's mean PI decreased from 47.86% to 23.95% after treatment (P = 0.005). The mean PI in the post-treatment lymph nodes was 24.47%. A nodal post-NACT PI of less than 10% and progesterone receptor-positive tumor status were associated with better survival, as all such patients are alive. A high PI after NACT was associated with recurrence or death. All of the patients who showed an excellent clinical response had either a decrease in the PI or an absence of a high level of VEGF after NACT. Most patients exhibited persistent expression of VEGF after NACT. Pathologic response in the primary tumor did not correlate with the response in the lymph nodes or with overall survival. NACT reduces the size and PI of the primary breast tumor independent of the patient's node status. The PI may be an early means by which to identify tumors most likely to reduce in size with chemotherapy. A low PI after NACT is associated with better survival. There is persistent expression of VEGF in post-NACT residual breast carcinoma. Thus, anti-VEGF drugs after conventional chemotherapy may benefit patients with residual carcinoma.

VEGF-C expression in breast cancer: clinical importance

It is well known that angiogenesis and lymphangiogenesis play important roles in tumor occurrence and progression. The vascular endothelial growth factor (VEGF) family is the most important family of proteins involved in angiogenesis, and VEGF-C is the most important molecule in lymphangiogenesis. Lymphangiogenesis plays an important role in lymphovascular invasion, metastasis to regional lymph nodes, and distant organ metastasis. In this study, the rate of VEGF-C was investigated in 217 patients with breast cancer. VEGF-C was evaluated by immunohistochemistry and its expression was compared with that of well-known prognostic indicators, such as tumor stage and grade, axillary lymph node involvement, estrogen and progesterone receptor status, c-erb-B2 expression, and extent of lymphovascular invasion. The patient population included 8 men, in addition to women before (n=108), during (n=9), and after (n=92) menopause. Patients had been diagnosed with invasive ductal (n=181) or invasive lobular (n=22) carcinoma, mixed (n=8) or medullary (n=1) carcinoma, or ductal carcinoma in situ (n=5). Tumors ranged from stage 0 to IV and grade I to III and the distribution of estrogen-positive (n=100) and estrogen-negative (n=110) receptor tumors was almost equal. The number of patients with c-erbB2 tumors ranged from 21 to 49 for each tumor stage, and the number of patients with VEGF-C-negative tumors ranged from 28 to 59 for each tumor stage. No important association between VEGF-C expression and other prognostic indicators was found. However, this may be a result of the lack of standardization among the methods used to determine VEGF-C expression. Also, the lymphangiogenic effect may not be overt because of the variety of VEGFR-3 variants, which included nonfunctional variants. To determine the relationship among angiogenesis, lymphangiogenesis, and prognosis, more standardized methods to demonstrate the angiogenesis, and prospective studies to cover a larger, more homogenous patient population are needed.

Tumor-specific VEGF-A and VEGFR2 in postmenopausal breast cancer patients with long-term follow-up. Implication of a link between VEGF pathway and tamoxifen response

Vascular endothelial growth factor (VEGF-A) is considered a prognostic indicator for clinical outcome in breast cancer. Conflicting results nevertheless exist and there is a need for larger studies including untreated patients in order to clarify the importance of tumor-specific VEGF-A regarding prognosis as well as potential links to predictive treatment information. VEGF-A and its receptor, vascular endothelial growth receptor 2 (VEGFR2), were therefore analyzed by immunohistochemistry in postmenopausal breast cancers enrolled in a clinical trial where patients were randomized to adjuvant tamoxifen treatment (n = 124) for 2 years or no treatment (n = 127) with a median follow-up of 18 years. The tumors were arranged in a tumor tissue microarray system enabling parallel analysis of the angiogenic factors and hormone receptor status. Tumor-specific expression of VEGFR2 correlated strongly with expression of VEGF-A and progesterone receptor (PR) negativity, whereas VEGF-A was not associated with hormone receptor status. Among patients with estrogen receptor (ER) positive (fraction > 10%) tumors, there was a statistically significant tamoxifen response in VEGF-A negative tumors at both 10-year and 18-year disease-free survival (DFS), contrasting to VEGF-A positive tumors who had no beneficial effect of tamoxifen. A treatment-interaction variable indicated a marked difference in tamoxifen response depending on VEGFA-status in terms of DFS at 10 and 18 years of follow-up, p = 0.046 and p = 0.039, respectively. VEGFR2 status did not yield significant predicitve information for tamoxifen response in patients with ER fraction > 10%, whereas in patients with ER fraction > 90% both VEGF-A and VEGFR2 status were associated with tamoxifen treatment effect.

Endothelin-1-, endothelin-A-, and endothelin-B-receptor expression is correlated with vascular endothelial growth factor expression and angiogenesis in breast cancer

PURPOSE

Endothelin-1 (ET-1) and its receptors (ET(A)R and ET(B)R), referred to as the endothelin (ET) axis, are overexpressed in breast carcinomas, and influence tumorigenesis and tumor progression by various mechanisms, including angiogenesis. The objective of the study was to clarify if expression of the ET axis participates in angiogenesis of breast carcinoma

EXPERIMENTAL DESIGN

We analyzed expression of ET-1, ET(A)R, ET(B)R, and vascular endothelial growth factor (VEGF) immunohistochemically in 600 tissue array specimens from 200 paraffin-embedded breast carcinomas performing tissue microarray technology. Microvessel density (MVD) was determined by counting microvessels (identified by factor VIII) in each core specimen.

RESULTS

Moderate or strong immunostaining was observed for ET-1 in 25.4%, for ET(A)R in 43.7%, and for ET(B)R in 22.2% of breast carcinomas. Of all cases, 44.7% showed significant expression of VEGF. MVD varied between different tumor specimens (range, 0-80; median, 17). We observed a statistically significant correlation between MVD and ET expression status with higher MVD in ET-positive tumors. Moreover, expression of VEGF was found more frequently in tumors with overexpression of the ET axis (each P < 0.001). Staining of VEGF was correlated positively with MVD CONCLUSIONS: These results indicate that increased ET-1, ET(A)R, and ET(B)R expression is associated with increased VEGF expression and higher vascularity of breast carcinomas and, thus, could be involved in the regulation of angiogenesis in breast cancer. Our findings provide evidence that the expression pattern of the ET-axis and in particular of ET(A)R may have clinical relevance in future antiangiogenic targeted therapies for breast cancer.

Clinical relevance of amphiregulin and VEGF in primary breast cancers

The characterization of novel prognostic markers in breast cancer is necessary to improve the identification of high-risk populations. In our study, the prognostic significance of VEGF and amphiregulin (AR) was investigated and compared to conventional prognostic factors in primary breast cancers. The analysis was performed using enzyme-linked immuno-assay in a series of 193 patients, and univariate and multivariate analysis were performed in the overall population as well as in pre- and post-menopausal patients subdivided in node-negative (N-) and node-positive (N+) subsets. AR (median, 44.8 pg/mg protein) appeared strongly correlated with progesterone receptors (PgR) (p = 0.0018) in the premenopausal N+ population, and with uPA (p= 0.020) and VEGF (p= 0.0053) in the postmenopausal/N+ patients. Despite these attractive data, AR expression was not significant for recurrence or survival outcome. Data revealed strong correlation between VEGF and uPA, and PAI-1, in the N+ population. Moreover, patients with high VEGF levels displayed poor outcome, with an increased risk for N+ subset. These data were confirmed by multivariate analysis that presented histologic grade (HR, 10.55, p = 0.001) and VEGF (HR, 3.89, p = 0.03) as the prominent prognostic markers for overall survival for the N+ population. Furthermore, infiltrating ductal carcinomas (IDC) were shown to express higher levels of both uPA (p < 0.0001) and VEGF (p = 0.002) than intralobular carcinomas. This retrospective study reinforces the pejorative biological role of VEGF in the progression of breast tumors. Our data also suggest that VEGF and uPA might play particular role in the biology and progression of IDC.

Expression of vascular endothelial growth factor, hypoxia inducible factor 1alpha, and carbonic anhydrase IX in human tumours

AIMS

To measure vascular endothelial growth factor (VEGF-A) mRNA in a large, diverse cohort of tumours and to investigate whether VEGF-A expression is associated with markers of hypoxia, including hypoxia inducible factor 1alpha (HIF-1alpha) and carbonic anhydrase IX (CA9).

METHODS

The expression of VEGF-A and CA9 was assessed in 5067 fresh frozen human tissue samples and 238 cell lines by DNA microarray analysis. In addition, tissue microarrays were constructed from 388 malignancies to investigate the expression of VEGF-A and HIF-1alpha by in situ hybridisation and immunohistochemistry, respectively.

RESULTS

VEGF-A was significantly upregulated in primary malignancies of the breast, cervix, colon and rectum, oesophagus, head and neck, kidney, ovary, skin, urinary system, and white blood cells by DNA microarray analysis. However, VEGF-A expression only correlated with CA9 expression in renal tissues. In the tissue microarrays, HIF-1alpha positive cores showed a significant increase in VEGF-A expression in lung, ovary, soft tissue, and thyroid malignancies.

CONCLUSIONS

The expression of VEGF-A is upregulated in a large proportion of human malignancies, and may be associated with markers of hypoxia. VEGF-A expression can be induced in the absence of hypoxia and hypoxia does not always provoke VEGF-A upregulation in tumours.

Hypoxia-inducible factor 1α/vascular endothelial growth factor axis in astrocytomas. Associations with microvessel morphometry, proliferation and prognosis

Hypoxia-inducible factor (HIF)-1alpha is a transcription factor that promotes ischaemia-driven angiogenesis. The aim of this study was to determine the relation of HIF-1alpha to vascular endothelial growth factor (VEGF; an important angiogenic molecule in brain tumours), p53 expression, angiogenesis, proliferative potential and clinical outcome in a large series of diffuse astrocytomas. Expression of HIF-1alpha, VEGF, Ki-67 (a proliferation-associated marker) and p53 was determined immunohistochemically in 83 adult patients with supratentorial diffuse astrocytomas. Microvessels, highlighted by means of anti-CD34 immunohistochemistry, were enumerated with computer-assisted image analysis. Although HIF-1alpha and VEGF were expressed in the majority of cases, their levels increased significantly with increasing grade and proliferative potential. HIF-1alpha positively correlated with microvessel counts and VEGF with total vascular area and the presence of rounder vessel sections. There was a positive correlation of VEGF with p53 expression in astrocytomas and anaplastic astrocytomas. In univariate analysis, both VEGF and HIF-1alpha were associated with shortened survival in the entire cohort, but lost significance when grades II/III and grade IV were analysed separately. Multivariate analysis revealed that the combination of HIF-1alpha with grade was a significant prognostic indicator. HIF-1alpha expression may be used to refine the prognostic information provided by grade in patients with diffuse astrocytomas. Its adverse prognostic effect is most likely mediated by hypoxia, the driving force for HIF-1alpha accumulation.

Basic fibroblast growth factor and vascular endothelial growth factor serum levels in breast cancer patients and healthy women: useful as diagnostic tools?

INTRODUCTION

The aim of the present study was to analyze the relationship between the expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in breast cancer cells and the corresponding serum levels in individual patients. The study also evaluated the potential of serum levels of the two growth factors as diagnostic markers in a case-control study.

METHODS

VEGF expression and bFGF expression were determined in 62 and 63 tumor samples, respectively. Serum VEGF and bFGF levels were determined in 54 and 65 healthy women and in 69 and 73 breast cancer patients, respectively, using a quantitative sandwich enzyme immunoassay technique.

RESULTS

A direct correlation was observed between VEGF expression and bFGF expression in individual tumors (P = 0.001) and between serum levels (P = 0.038) in individual patients, but not between tumor cell expression and the corresponding serum level for either growth factor. Median values of serum levels in healthy women and breast cancer patients were not different for VEGF (P = 0.055), but were significantly different for bFGF (P < 0.001). The receiver operating characteristic curve identified a serum bFGF concentration of 1.0 pg/ml, with 84.9% sensitivity and 63.1% specificity, as the best cut-off value to discriminate between healthy women and breast cancer patients. An age-based subgroup analysis showed that serum values of patients older than 70 years of age mainly contributed to the high accuracy.

CONCLUSIONS

Our data repropose bFGF as a noninvasive diagnostic tool for breast cancer.

Glomeruloid microvascular proliferation is associated with p53 expression, germline BRCA1 mutations and an adverse outcome following breast cancer

Glomeruloid microvascular proliferation (GMP) in breast cancer independently adversely affected survival (relative risk 1.9, 95% CI: 1.2-3.0), particularly among women who received adjuvant chemotherapy (10-year survival 27 vs 69%, P=0.0003), and was significantly associated with p53 overexpression and BRCA1 germline mutations. The presence of GMP may influence treatment decisions.

Evaluation of the Prognostic Role of Vascular Endothelial Growth Factor and Microvessel Density in Stages I and II Breast Cancer Patients

In this study, we retrospectively evaluated the expression of vascular endothelial growth factor (VEGF) and microvessel density (MVD) in 228 and 213 specimens, respectively, from stages I and II breast cancer patients (pts) enrolled in a randomized phase III adjuvant chemotherapy trial comparing epirubicin to CMF, while tamoxifen was given to all postmenopausal pts. The expression of VEGF and MVD was assessed on tissue sections formalin-fixed and paraffin-embedded by immunohistochemical staining using anti-VEGF antibody of human origin and anti-CD34 monoclonal antibody. Univariate and multivariate analysis were performed using chi squared test, log-rank test and Cox's regression model. Sixty four of 228 pts were classified as VEGF positive (28%) with no significant difference in the two treatment arms. In 213 pts evaluated for CD34, 103 pts (48%) were classified as MVD high. No significant association between VEGF and MVD was found, and neither were they correlated with many known prognostic factors such as age, tumor size, nodal status, and histological grade. The only significant correlations observed were between VEGF and estrogen receptor (ER) status (p = 0.013) and between MVD and HER2 overexpression (p = 0.023). At a median follow up of 96 months VEGF and MVD were not correlated with relapse-free survival (RFS) and overall survival (OS) in all pts and in pts assigned to one of the two treatment arms. In conclusion, VEGF and MVD retrospectively evaluated, cannot be considered prognostic factors in node negative (N-) high risk and node positive (N+) breast cancer pts treated with two different regimens of adjuvant chemotherapy.

Significance of serum vascular endothelial growth factor, insulin-like growth factor-I levels and nitric oxide activity in breast cancer patients

Vascular endothelial growth factor (VEGF) is used to evaluate the angiogenic activity in breast carcinoma. Nitric oxide (NO) and insulin-like growth factor-I (IGF-I) are also implicated in breast tumorigenesis, including angiogenesis. We measured serum VEGF, IGF-I and nitrate+nitrite levels in 38 patients with metastatic and 23 with nonmetastatic breast cancer and in 16 controls. Serum VEGF and IGF-I levels were higher in patients with metastatic disease than in those with nonmetastatic disease or in controls (P<0.001). Serum nitrate+nitrite levels were higher in patients with metastatic and nonmetastatic disease than in controls (P<0.001). Patients with visceral metastasis and local metastasis had higher serum VEGF and nitrate+nitrite levels than patients with bone metastasis (P<0.05). In the metastatic disease group, there was a positive correlation between serum VEGF levels and nitrate+nitrite levels (r=0.436, P<0.05). Within the group with nonmetastatic disease, premenopausal patients had higher serum IGF-I levels than did postmenopausal patients (P<0.001). NO may involve an angiogenic process that is stimulated by VEGF in breast carcinoma. Larger studies are required to clarify these suggestions.

Angiogenesis: prognostic and therapeutic implications in gynecologic and breast malignancies

PURPOSE OF REVIEW

Growth, invasion and metastasis of malignant tumors depend on angiogenesis, which is therefore considered an attractive therapeutic target and indicator of clinical outcome. Summarizing the results of very recent studies, we discuss the clinical relevance of vascularization of breast and gynecological tumors.

RECENT FINDINGS

The prognostic values of directly assessed vascularity (microvessel density) and angiogenic factors have been confirmed for these malignancies, despite few contradictory results that may be due to methodological inaccuracy. In addition, many studies point to a role of angiogenesis as a predictor of response to both antiangiogenic and conventional chemotherapy or radiotherapy. For a conclusive evaluation, however, further studies covering all clinically relevant subgroups of patients are needed. Novel therapeutic approaches with inhibitors of angiogenesis are promising, although the adaptation of most experimentally proven approaches to clinical practice appears to be a laborious process. Furthermore, for an appropriate clinical evaluation of these drugs, newly defined endpoints of treatment and new monitoring systems reflecting their mode of action and the anticipated biological effects are required.

SUMMARY

The prognostic and predictive value of angiogenic factors and microvessel density has been confirmed. Antiangiogenic therapy will most likely play an important role in future clinical management of malignant diseases.