Prognostic significance of vascular endothelial growth factor protein in node-negative breast carcinoma

Effect of tamoxifen on serum IL-18, vascular endothelial growth factor and nitric oxide activities in breast carcinoma patients

Vascular endothelial growth factor (VEGF) is a multi-functional cytokine that has been suggested to be a major angiogenic factor in breast cancer. Nitric oxide (NO) is a potent biological molecule that participates in the multi-step process of carcinogenesis. Interleukin (IL)-18 has been shown to have potent anti-tumour effects. In this study, we investigated the effect of tamoxifen therapy on serum VEGF, NO and IL-18 activity in breast cancer patients. Serum levels of VEGF, nitrate + nitrite and IL-18 were measured in 34 postmenopausal breast cancer patients before and 3 months after the tamoxifen therapy. Both serum VEGF and IL-18 levels decreased after tamoxifen therapy (P = 0.051, P < 0.05, respectively). Serum VEGF levels increased in patients with endometrial thickness, while patients without endometrial thickness had a significant reduction in serum VEGF levels after therapy (P < 0.05). Serum nitrate + nitrite levels increased after the therapy, but this was not statistically significant (P > 0.05). A decrease in serum VEGF levels with tamoxifen therapy may be a reflection of reduced angiogenic activity in patients without endometrial thickness. The negative effect of tamoxifen therapy on IL-18, which is known to have a potent antitumour activity, may be related to the decreased tumour growth by induction of NO and reduction of VEGF activity as a feedback mechanism.

Association between HER-2/neu and vascular endothelial growth factor expression predicts clinical outcome in primary breast cancer patients

PURPOSE

Activation or overexpression of HER-2/neu is associated with up-regulation of vascular endothelial growth factor (VEGF) in human breast cancer cells in vitro. Preclinical experiments indicate that increased expression of VEGF may in part mediate the biologically aggressive phenotype of HER-2/neu-overexpressing human breast cancer. It was the purpose of this study to: (a). evaluate the association between HER-2/neu and VEGF expression in a large clinical cohort of primary breast cancer patients; (b). compare the prognostic significance of VEGF isoforms; and (c). analyze the combined effects of HER-2/neu and VEGF on clinical outcome.

EXPERIMENTAL DESIGN

HER-2/neu and VEGF were measured by ELISA in primary breast tumor tissue lysates from 611 unselected patients with a median clinical follow-up of 50 months. At least six VEGF isoforms consisting of 121, 145, 165, 183, 189, or 206 amino acids are generated as a result of alternative splicing. The VEGF(121-206) ELISA uses antibodies that bind to VEGF(121) and, therefore, detects all of the VEGF isoforms with 121 and more amino acids. The VEGF(165-206) ELISA uses antibodies that bind to VEGF(165) and, therefore, detects all of the VEGF isoforms with 165 and more amino acids. VEGF(121-206) and VEGF(165-206) were analyzed both as continuous and categorical variables, using detectable expression as a cutoff for positivity. Cell lines with defined HER-2/neu expression levels were used to establish a cutoff point for HER-2/neu overexpression in breast tumor samples.

RESULTS

Our findings indicate a significant positive association between HER-2/neu and VEGF expression. VEGF(121-206) and VEGF(165-206) expression was detectable in 88 (77.2%) and 100 (87.7%), respectively, of the 114 patients with HER-2/neu-overexpressing tumors, in contrast to 271 (54.5%) and 353 (71.0%), respectively, of the 497 patients with nonoverexpressing tumors (chi(2) test: P < 0.001 for both VEGF(121-206) and VEGF(165-206)). VEGF(121-206) and VEGF(165-206) demonstrate a comparable prognostic significance for survival in unselected primary breast cancer patients (univariate analysis: VEGF(121-206), P = 0.0068; VEGF(165-206), P = 0.0046; multivariate analysis: VEGF(121-206), P = 0.1475; VEGF(165-206), P = 0.1483). When the analyses were performed separately for node-negative and node-positive patients, VEGF(121-206) and VEGF(165-206) were of prognostic significance for survival only in node-positive patients (univariate analysis: VEGF(121-206), P = 0.0003; VEGF(165-206), P = 0.0038; multivariate analysis: VEGF(121-206), P = 0.0103; VEGF(165-206), P = 0.0150). A biological concentration-effect relationship between VEGF expression and survival (VEGF(121-206), P = 0.0280; VEGF(165-206,) P = 0.0097) suggests that VEGF levels, as determined by ELISA, could be of importance as a predictive marker for therapeutic strategies that target VEGF. Combining HER-2/neu and VEGF(121-206)/VEGF(165-206) results in additional prognostic information for survival (VEGF(121-206), P = 0.0133; VEGF(165-206), P = 0.0092).

CONCLUSION

The positive association between HER-2/neu and VEGF expression implicates VEGF in the aggressive phenotype exhibited by HER-2/neu overexpression, and supports the use of combination therapies directed against both HER-2/neu and VEGF for treatment of breast cancers that overexpress HER-2/neu.

Breast cancer: the role of angiogenesis and antiangiogenic therapy

Angiogenesis plays a role in breast cancer development. Preclinical and clinical evidence is reviewed. Development of targeted antiangiogenic agents provides new challenges to clinical trial design. Current antiangiogenic therapy with traditional agents and novel agents are classified and reviewed.

Antiangiogenic strategies, compounds, and early clinical results in breast cancer

Angiogenesis is a multi-step process leading to the formation of new blood vessels from pre-existing vasculature and it is necessary for primary tumor growth, invasiveness and development of metastasis. Experimental and clinical data demonstrated that breast cancer is an angiogenesis-dependent disease and that the vascular endothelial growth factor (VEGF) family plays a key role it being a highly expressed and selective endothelial cell growth factor. Preclinical studies have shown that the angiogenic switch occurs early in the multistage process of breast cancer development. Targeting the molecular pathways involved in tumor progression by biologically-designed treatments is a new therapeutic paradigm aimed to reach cancer growth control. A number of possible therapeutic targets for antiangiogenic agents have been identified. Here we discuss the therapeutic approach based on inhibition of angiogenesis in the context of breast cancer with a focus on the early clinical studies on antiangiogenic agents in advanced disease.

Stromal expression of vascular endothelial growth factor correlates with tumor grade and microvessel density in mammary phyllodes tumors: A multicenter study of 185 cases

A retrospective review of 185 mammary phyllodes tumors (105 benign, 51 borderline, 29 malignant) from 4 centers was performed by immunohistochemistry to investigate the expression of vascular endothelial growth factor in the epithelial and stromal cells of mammary phyllodes tumors. The correlation of vascular endothelial growth factor with tumor grade, stromal cell nuclear pleomorphism, cellularity, mitotic rate, margin histomorphology, and the stromal microvessel density was evaluated. Vascular endothelial growth factor expression was found in the epithelium in 29% and in the stromal cells in 31% of cases. There was significant increase of vascular endothelial growth factor expression in the stromal cells with increasing degree of malignancy, but not the epithelium. Microvessel density in the stroma also showed significant correlation with tumor malignancy, and a correlation was shown with the stromal vascular endothelial growth factor expression. Statistical overlap of stromal vascular endothelial growth factor and microvessel density in predicting malignancy suggests that angiogenesis may be an effector mechanism for vascular endothelial growth factor. Assessment of stromal VEGF may be useful as an adjunctive diagnostic criterion in the histologic assessment of malignancy in phyllodes tumors.

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.

Transduction of soluble Flt-1 gene to peritoneal mesothelial cells can effectively suppress peritoneal metastasis of gastric cancer

The prognosis of gastric cancer with peritoneal metastasis has not improved. Despite many promising studies, gene therapy has limited clinical application because of the lack of suitable vector systems to enable selective gene transduction to tumor cells. The aim of this study was to clarify whether gene therapy targeted to peritoneal mesothelial cells (PMCs) can inhibit peritoneal dissemination of gastric cancer. In vitro experiments showed that adenovirus expressing LacZ infected human omental tissue-derived PMCs more efficiently than human gastric cancer cell lines MKN1 and MKN45. When adenovirus expressing LacZ was injected into the peritoneal cavity of nude mice, the expression was detected in the peritoneum for at least 4 weeks. Furthermore, when adenovirus expressing soluble Flt-1 (Ad-sFLT-1) was i.p. administered in vivo, a high level of sFlt-1 protein could be detected in peritoneal lavage for 8 weeks. When MKN45 cells were i.p. inoculated 3 days after adenoviral vector injection, Ad-sFLT-1 markedly reduced the number of metastatic nodules larger than 1 mm in diameter on the peritoneal surface, and significantly prolonged the survival of nude mice without any significant side effects. Thus, peritoneal dissemination was significantly suppressed by a single i.p. injection of Ad-sFlt-1. Anti-angiogenic gene therapy targeted to PMCs could be a novel and practical strategy against peritoneal dissemination of gastric cancer, because it does not require tumor-specific gene transfer.

Treatment of experimental breast cancer using interleukin-12 gene therapy combined with anti–vascular endothelial growth factor receptor-2 antibody

We have shown previously that interleukin-12 (IL-12) gene therapy induced strong antitumor effects in several syngeneic murine tumor models including 4T1 mammary adenocarcinoma. Antiangiogenic treatment with a monoclonal antibody (mAb) directed against the vascular endothelial growth factor receptor-2 (VEGFR-2) is another promising treatment approach that can cause transient suppression of tumor growth. We hypothesized that the combination of IL-12 gene therapy and anti-VEGFR-2 mAb will achieve better antitumor and antimetastatic effects against 4T1 adenocarcinoma than each treatment alone via implementation of different mechanisms. Administration of anti-VEGFR-2 mAb into BALB/c mice bearing s.c. 4T1 tumors induced significant suppression of tumor growth, as did intratumoral administration of naked IL-12 DNA. The combined treatment with anti-VEGFR-2 mAb and IL-12 DNA resulted in significantly enhanced inhibition of tumor growth as compared with each treatment alone. This combination was also effective against spontaneous lung metastases. In T-cell–deficient nude mice, both IL-12 DNA and anti-VEGFR-2 mAb were effective in suppressing tumor growth. In T-cell- and natural killer cell–deficient scid/beige mice, only anti-VEGFR-2 mAb was effective, suggesting that natural killer cells are involved in the antitumor effects induced by IL-12 DNA. In both types of immunodeficient mice, the combination of anti-VEGFR-2 mAb and IL-12 DNA was as effective in suppressing 4T1 tumor growth as anti-VEGFR-2 mAb alone. Antitumor effects of anti-VEGFR-2 mAb were associated with the inhibition of angiogenesis within the tumors, whereas the antiangiogenic effect of IL-12 gene therapy was not detected. Our results show a therapeutic benefit of combining IL-12 gene therapy and anti-VEGFR-2 mAb for cancer treatment.

Molecular detection of micrometastatic breast cancer in histopathology-negative axillary lymph nodes correlates with traditional predictors of prognosis: an interim analysis of a prospective multi-institutional cohort study

OBJECTIVE

We sought to establish the clinical relevance of micrometastatic disease detected by reverse transcription polymerase chain reaction (RT-PCR) in axillary lymph nodes (ALN) of breast cancer patients.

BACKGROUND

The presence of ALN metastases remains one of the most valuable prognostic indicators in women with breast cancer. However, the clinical relevance of molecular detection of micrometastatic breast cancer in sentinel lymph nodes (SLN) and nonsentinel ALN has not been established.

METHODS

Four hundred eighty-nine patients with T1-T3 primary breast cancers were analyzed in a prospective, multi-institutional cohort study. ALN were analyzed by standard histopathology (H&E staining) and by multimarker, real-time RT-PCR analysis (mam, mamB, muc1, CEA, PSE, CK19, and PIP) designed to detect breast cancer micrometastases.

RESULTS

A positive marker signal was observed in 126 (87%) of 145 subjects with pathology-positive ALN, and in 112 (33%) of 344 subjects with pathology-negative ALN. In subjects with pathology-negative ALN, a positive marker signal was significantly associated with traditional indicators of prognosis, such as histologic grade (P = 0.0255) and St. Gallen risk category (P = 0.022). Mammaglobin was the most informative marker in the panel.

CONCLUSION

This is the first report to show that overexpression of breast cancer-associated genes in breast cancer subjects with pathology-negative ALN correlates with traditional indicators of disease prognosis. These interim results provide strong evidence that molecular markers could serve as valid surrogates for the detection of occult micrometastases in ALN. Correlation of real-time RT-PCR analyses with disease-free survival in this patient cohort will help to define the clinical relevance of micrometastatic disease in this patient population.

No association between serum levels of insulin-like growth factor-I, vascular endothelial growth factor, prolactin and clinicopathological characteristics of breast carcinoma after surgery

BACKGROUND

Angiogenesis is essential for tumour growth and metastasis. Vascular endothelial growth factor (VEGF) has been suggested as the major angio-genic factor in breast carcinoma. Both insulin-like growth factor-I (IGF-I) and prolactin are involved in the progression of breast cancer at least partly by stimulating angiogenesis.

AIM

The aim of the present study was to investigate the association between serum IGF-I, VEGF and prolactin levels and clinicopathological characteristics of breast carcinoma.

METHODS

Serum IGF-I, VEGF and prolactin levels were measured in breast cancer patients and controls and these levels were compared with well-known clinicopathological characteristics of breast carcinoma, including tumour size, axillary lymph node and oestrogen/progesterone receptor status, tumour grade and disease stage.

RESULTS

Serum prolactin, VEGF and IGF-I levels were found to be similar in breast cancer patients and control subjects (P > 0.05). When the patients were divided into groups according to their tumour size, axillary lymph node status, tumour grade, oestrogen/progesterone receptor status and disease stage, no significant differences in serum prolactin, VEGF and IGF-I levels were found among the groups (P > 0.05).

CONCLUSIONS

The present study failed to demonstrate an association between serum levels of VEGF, IGF-I and prolactin and well-known clinicopathological characteristics of breast carcinoma.

Non‐Small Cell Lung Cancer and Antiangiogenic Therapy: What Can Be Expected of Bevacizumab?

There is an urgent need for new therapies to treat non-small cell lung cancer (NSCLC), as progress with current chemotherapy regimens has been limited. The roles of vascular endothelial growth factor (VEGF) in promoting tumor angiogenesis, maintaining existing vasculature, and contributing to resistance to traditional therapies, together with its negative prognostic significance in NSCLC, make it an appropriate target for therapy. Bevacizumab (Avastin; Genentech Inc., South San Francisco, CA), a monoclonal antibody directed against VEGF, has shown promise in treating a number of different cancers. In a recent phase II trial in patients with advanced metastatic NSCLC, the addition of bevacizumab to standard carboplatin/paclitaxel chemotherapy produced a significantly longer time to progression (32.1 versus 18.4 weeks) and greater response rate (31% versus 19% [not significant]) than chemotherapy alone. In the subset of patients with nonsquamous histologies, response rates and survival were further enhanced, with a mean survival time of 17.9 months versus 12.3 months with chemotherapy alone. Bevacizumab was generally well tolerated and did not appear to increase the incidences or severities of the nausea/vomiting, neuropathy, and renal toxicity that are typically associated with carboplatin/paclitaxel chemotherapy. Adverse events in phase I and II studies included hypertension, thrombosis, proteinuria (with occasional nephrotic syndrome), and epistaxis. Serious tumor-related bleeding episodes (hemoptysis/hematemesis) appear to be the main safety concern in patients with NSCLC, with squamous cell histology as a possible risk factor. Further work is needed to identify the best way to use bevacizumab in NSCLC, including use in combination with other biologic agents and in the adjuvant setting.

Bevacizumab in the Treatment of Breast Cancer: Rationale and Current Data

Vascular endothelial growth factor (VEGF) has emerged as a key target for the treatment of cancer. As the ligand to the VEGF receptor, it plays a central role in promoting tumor angiogenesis. Overexpression of VEGF leads to poor outcomes in patients with breast cancer and other tumors. Preclinical studies have shown that the humanized monoclonal antibody to VEGF, bevacizumab (Avastin; Genentech, Inc., South San Francisco, CA), can reduce tumor angiogenesis and inhibit the growth of solid tumors, either alone or in combination with chemotherapy. As a single agent or added to vinorelbine, bevacizumab has produced encouraging results in phase II clinical trials in patients with refractory metastatic breast cancer. When added to capecitabine chemotherapy in a phase III trial, bevacizumab produced a greater response rate, but did not prolong progression-free survival. This may reflect the late disease stage and poor prognostic factors in the patient population. A large, ongoing, phase III, cooperative group trial is evaluating the effect of bevacizumab in combination with paclitaxel as first-line therapy for metastatic disease. The adverse effect profile of bevacizumab differs from that of cytotoxic chemotherapy and includes hypertension, proteinuria, thrombosis, and epistaxis.

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.

Progestin-dependent induction of vascular endothelial growth factor in human breast cancer cells: preferential regulation by progesterone receptor B

The progesterone receptor (PR) is a ligand-dependent transcription factor that promotes progestin-stimulated expression of target genes. Two functional PR isoforms, PRA and PRB, are expressed in progestin-responsive cells. PRA and PRB have distinct roles in gene expression and in mammary gland development. One role of PRs in T47-D cells is regulating expression of vascular endothelial growth factor (VEGF), a potent angiogenic growth factor. This study explores the isoform specificity of this PR function using parental T47-Dco cells that express both PRA and PRB and clonal derivatives that express either PRA (YA cells) or PRB (YB cells) or lack PR (Y cells). Treatment with progesterone induces VEGF mRNA and protein approximately 2-fold in T47-Dco and YA cells and 3-7-fold in YB cells, suggesting that PRA inhibits PRB-dependent induction of VEGF. This is consistent with the observation that clinically relevant progestins induce a much higher level of VEGF in YB cells than in YA cells. Another novel finding in this report is that estradiol (10(-8) M) induces VEGF production from YB cells. However, this induction is not blocked by 100-fold excess tamoxifen or ICI-182,780. Moreover, both tamoxifen (10(-6) M) and ICI-182,780 (10(-6) M) function as agonists for VEGF in YB cells. Small interfering RNA against PR or estrogen receptor abrogated estradiol and tamoxifen induction, indicating that the agonist-like response of these compounds in YB cells is estrogen receptor and PR dependent. Estradiol, tamoxifen, and ICI-182780 also induce VEGF in BT-474 cells when their PRB levels were elevated by transfecting an expression plasmid for PRB, but not when the cells were transfected with vector alone. These results indicate that (a) PRB preferentially regulates VEGF expression in breast cancer cells and (b) PRB-enriched tumor cells may produce more VEGF, have a better developed vasculature, and potentially are more resistant to tamoxifen and ICI-182,780 than cells that express an equivalent or higher level of PRA than PRB. These results imply that PRB-enriched breast tumors may respond well to anticancer therapies that include inhibitors of angiogenesis.

Tumor specific VEGF-A and VEGFR2/KDR protein are co-expressed in breast cancer

Angiogenesis is a prognostic indicator in primary breast cancer regulated by specific angiogenic factors and their receptors. Vascular endothelial growth factor-A (VEGF-A), so far considered the most important, acts through dimerization of the receptor VEGFR2/KDR within the receptor tyrosine kinase family of VEGF receptors. In order to study the interplay between VEGF-A and VEGFR2/KDR in breast cancer we evaluated their expression by immunohistochemistry in 102 breast cancers organized in a tumor tissue array system allowing semi-quantitative evaluation of cytoplasmatic staining intensity. In addition, VEGF-A165 was analyzed by an enzyme immuno assay (ELISA) in protein extracts prepared from frozen tissue from 98 of 102 tumors included in the array. Cytoplasmatic staining of VEGF of varying intensity was observed in all samples and correlated with the ELISA results of VEGF content (p = 0.007). Interestingly, VEGFR2/KDR expression correlated with VEGF expression using immunohistochemistry, indicating that VEGF and VEGFR2/KDR may be co-expressed in breast cancer. Furthermore, high levels of VEGF-A165 in the protein extracts was associated with impaired short time survival but not long term survival whereas immunohistochemically assessed VEGF and VEGFR2/KDR were not significantly associated with survival. In summary, immunohistochemically based analysis of VEGF using a tumor tissue array system seems to be a useful method for VEGF quantification in breast cancer here validated using an ELISA based method. The tumor tissue array system enables opportunities of simultaneous analysis of markers engaged in angiogenesis justifying further studies using larger series of tumors.

Effects of PTK787/ZK222584, a tyrosine kinase inhibitor, on the growth of a poorly differentiated thyroid carcinoma: an animal study

The process of neoangiogenesis is induced by several mediators. Vascular endothelial growth factor (VEGF) plays a key role in tumor angiogenesis including thyroid carcinomas. The principal aim of this study was to test the hypothesis that inhibition of VEGF activity by PTK787/ZK222584 (PTK/ZK), a specific blocker of both VEGF-receptor tyrosine kinases, could inhibit the growth of a poorly differentiated thyroid cancer. Human follicular thyroid tumor xenografts were implanted sc into nude mice. Eight days following implantation, the animals were randomized into two groups (n = 10 each group). One group received PTK/ZK daily, and the other was treated with sodium chloride (control). Treatment was orally administered using a gastric tube. All animals were killed after 4 wk. Tumors, blood, and samples of other organs were taken for further examinations. Treatment with PTK/ZK induced a 41.4% reduction in tumor volumes. Necrosis of the tumors was detectable earlier in PTK/ZK-treated mice compared with controls. Immunohistochemistry revealed a significant decrease in neoangiogenesis in tumors of PTK/ZK-treated animals. Moreover, no compensatory overexpression of VEGF protein was detectable in the treated group. The compound was well tolerated by the animals without significant side effects on body weight or in general. These results showed that VEGF receptor blockade is a rational approach to the therapy of thyroid cancer. The combination of radioiodine or external radiation with VEGF receptor tyrosine kinase inhibitors might be a new option, especially for poorly differentiated thyroid cancers with limited or no response to conventional therapy.

Soluble vascular endothelial growth factor receptor 1, and not receptor 2, is an independent prognostic factor in acute myeloid leukemia and myelodysplastic syndromes

BACKGROUND

Vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) are major regulators of angiogenesis, which plays a key role in the growth and dissemination of solid tumors and hematologic neoplasms.

METHODS

The authors measured the plasma concentrations of soluble VEGFR1 (sVEGFR1) and sVEGFR2 in 133 patients with acute myeloid leukemia (AML) and in 80 patients with myelodysplastic syndromes (MDS) at the time of initial presentation and compared clinical behaviors.

RESULTS

A reverse correlation was observed between plasma sVEGFR1 levels and the rate of complete remission (CR) in patients with AML, but not in patients with MDS. In contrast, increased plasma levels of sVEGFR2 were correlated with a lower CR rate in patients with MDS, but not in patients with AML. Cox regression model analysis demonstrated that plasma levels of sVEGFR1, but not sVEGFR2, were independent prognostic factors in both patients with AML and patients with MDS.

CONCLUSIONS

The findings suggest that different mechanisms are involved in the pathophysiology of AML and MDS. The concentration of sVEGFR1 and sVEGFR2 in plasma should be considered a significant factor in guiding antiangiogenic therapy for AML and MDS. They may play a role in the pharmacodynamics of therapeutic agents that are supposed to bind directly to these receptors.

Expression of vascular endothelial growth factor in salivary gland carcinomas and its relation to p53, Ki-67 and prognosis

BACKGROUND

Vascular endothelial growth factor (VEGF) has been demonstrated to play an important role in tumor angiogenesis and to influence prognosis in many cancers. But, its significance in salivary gland carcinomas has not been elucidated. The authors investigated the association between VEGF expression and clinicopathological factors, p53, and Ki-67 to verify its validity as a prognostic factor.

METHODS

Surgical specimens from 45 patients with salivary gland carcinoma were examined for VEGF, p53, and Ki-67 expression by immunohistochemical staining. The results were compared with the clinicopathological factors and the relationships were correlated.

RESULTS

VEGF expression was low in 14 cases, moderate in 15 cases, and high in 16 cases. It was significantly correlated with a variety of clinicopathological factors such as TNM stage, perineural and vascular invasion, and recurrence. VEGF showed significant association with the expression of p53 but not with that of Ki-67. Univariate analysis showed that age, gender, lymph node metastasis, vascular invasion, p53, Ki-67, and VEGF expression correlate with prognosis. Multivariate analysis demonstrated that VEGF is an independent prognostic factor for patients with salivary gland carcinomas.

CONCLUSIONS

The results of this study suggest that VEGF expression is correlated with p53 expression and that it may have prognostic value in salivary gland carcinomas.

Prognostic Correlation of Basic Fibroblast Growth Factor and Vascular Endothelial Growth Factor in 1307 Primary Breast Cancers

This study was designed to investigate the possible relationship between the protein expression of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) with p53 status, breast cancer prognostic factors, metastatic site, and survival after adjuvant therapy. Basic fibroblast growth factor and VEGF expression were determined by enzyme-linked immunosorbent assays in cytosol specimens obtained from 1307 patients with T1-3 primary breast cancer (789 node-negative, 518 node-positive) diagnosed between 1990 and 1997. The median follow-up time was 70 months. Increased bFGF expression was more frequently found in tumors with low VEGF expression (r = -0.286; P = 0.095). Increased bFGF was associated with smaller tumors (P < 0.001), absence of axillary metastasis (P = 0.003), low S-phase fraction (P < 0.001), and longer recurrence-free survival (RFS; P = 0.0038) and overall survival (OS; P = 0.0316). Vascular endothelial growth factor was a prognostic factor for RFS (P < 0.0001) and OS (P < 0.0001) in univariate and multivariate analyses (RFS: 95% CI, 1.1-1.7; P = 0.036; OS: 95% CI, 1.2-2.2; P = 0.002), whereas bFGF expression was not correlated with RFS or OS. Increased VEGF content was correlated with shorter survival after adjuvant endocrine therapy (RFS, P = 0.0004; OS, P = 0.0009). Patients with estrogen receptor-negative disease were excluded from the analysis. Basic fibroblast growth factor was not a prognostic factor after adjuvant systemic therapy, nor was it related to metastatic site. Expression of VEGF is an independent prognostic factor for patients with primary breast cancer. High bFGF expression was related to good prognostic features and longer survival times, but did not add prognostic information in multivariate analysis. The results might implicate that different angiogenic pathways exist in human breast cancer.

Vascular endothelial growth factor is associated with the efficacy of endocrine therapy in patients with advanced breast carcinoma

BACKGROUND

Vascular endothelial growth factor (VEGF) is a mediator of angiogenesis and is associated with a poor prognosis in patients with primary breast carcinoma. In the current study, the authors investigated whether there was an association between VEGF levels in tumor tissues and response rates to first-line, systemic therapy in patients with advanced breast carcinoma.

METHODS

In 172 tumors from patients with primary breast carcinoma who developed distant metastases during follow-up, cytosolic levels of VEGF were measured using a quantitative enzyme-linked immunosorbent assay. Patients received either endocrine therapy (n = 96) or chemotherapy (n = 76) as first-line treatment after they were diagnosed with advanced disease.

RESULTS

In univariate logistic regression analysis for response to endocrine therapy in 96 patients, an increasing level of VEGF, as a log-transformed, continuous variable, was correlated with a poor rate of response (P = 0.043). In multivariate analysis, a significantly lower rate of response to first-line endocrine therapy was found for patients who had high VEGF levels compared with patients who had low VEGF levels (P = 0.025). Similar results were found for the subgroup of 82 patients who received tamoxifen (P = 0.011). An association of VEGF with response to first-line endocrine therapy was found in addition to a predictive impact for estrogen receptor/progesterone receptor status (P = 0.027). VEGF levels did not predict the rate of response to first-line chemotherapy.

CONCLUSIONS

The results demonstrated that the level of VEGF affects response to endocrine therapy independent of steroid hormone receptor status and may help to refine further the indication for this treatment in individual patients. Further studies are warranted to explain this underlying resistance to endocrine therapy.

Higher plasma vascular endothelial growth factor levels correlate with menopause, overexpression of p53, and recurrence of breast cancer

PURPOSE

Vascular endothelial growth factor (VEGF) is an important factor involved in angiogenesis. Many studies have reported that the expression of VEGF in breast cancer is an unfavorable prognostic factor. However, there are few studies that have analyzed blood VEGF levels because most used serum VEGF, generally thought to originate from platelets. We measured plasma VEGF levels, which evaluate the level of tumor-derived VEGF, in various breast diseases.

METHOD

We analyzed 15 patients with benign breast disease, 187 patients with primary breast cancer, 32 patients with no postoperative recurrence, and 56 patients with recurrence. Plasma VEGF levels were measured by ELISA.

RESULTS

Plasma VEGF levels were higher in malignant than in benign breast disease, and were also high in patients with recurrence or distant metastasis. In primary cases, higher VEGF levels were clearly correlated with menopause and overexpression of p53, and postmenopausal patients with high levels had a significantly lower disease-free survival rate.

CONCLUSION

These results suggest that plasma VEGF levels in breast cancer have a clinical significance in that they are associated with the extent or metastasis of malignant lesions and are involved in angiogenesis in postmenopausal patients.

The molecular detection of micrometastatic breast cancer

BACKGROUND

The rapid evolution of molecular technology and novel markers provides the opportunity to establish a more effective means to detect micrometastatic breast cancer. Given the controversies concerning application and clinical relevance, this review critically evaluates the current status of these molecular staging technologies.

DATA SOURCES

Breast cancer literature addressing (1). molecular detection methodologies (immunohistochemistry, reverse transcriptase polymerase chain reaction, and microarray analysis); (2). specific tissue applications such as lymph nodes, bone marrow aspirate, and peripheral blood; (3). expert commentary concerning the clinical applications and pitfalls of these technologies; and (4). recent data from our molecular diagnostics laboratory.

CONCLUSIONS

Molecular detection technologies such as reverse transcriptase polymerase chain reaction and microarray analyses are being developed that will likely have future application as cancer diagnostics. Further work is needed to establish assays that are validated by prospective clinical studies. Early identification of clinically relevant disease could lead to new treatment or staging approaches for breast cancer.

Structure and inhibitory effects on angiogenesis and tumor development of a new vascular endothelial growth inhibitor

Blocking angiogenesis is an attractive strategy to inhibit tumor growth, invasion, and metastasis. We describe here the structure and the biological action of a new cyclic peptide derived from vascular endothelial growth factor (VEGF). This 17-amino acid molecule designated cyclopeptidic vascular endothelial growth inhibitor (cyclo-VEGI, CBO-P11) encompasses residues 79-93 of VEGF which are involved in the interaction with VEGF receptor-2. In aqueous solution, cyclo-VEGI presents a propensity to adopt a helix conformation that was largely unexpected because only beta-sheet structures or random coil conformations have been observed for macrocyclic peptides. Cyclo-VEGI inhibits binding of iodinated VEGF165 to endothelial cells, endothelial cells proliferation, migration, and signaling induced by VEGF165. This peptide also exhibits anti-angiogenic activity in vivo on the differentiated chicken chorioallantoic membrane. Furthermore, cyclo-VEGI significantly blocks the growth of established intracranial glioma in nude and syngeneic mice and improves survival without side effects. Taken together, these results suggest that cyclo-VEGI is an attractive candidate for the development of novel angiogenesis inhibitor molecules useful for the treatment of cancer and other angiogenesis-related diseases.

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.

Why cyclooxygenase-2 inhibition plus chemotherapy?

New approaches to treating cancers are needed. Preclinical studies have identified numerous candidate genes/proteins that promote the cancer process. Cyclooxygenase-2 (COX-2) is a reasonable "target" because it is found in many epithelial tumors, has been shown to portend a poor prognosis, and is involved in many processes that promote cancer progression and chemotherapy resistance. Inhibition of COX-2 also has the potential to provide supportive care to patients with cancer. This article describes the rationale for performing a phase II trial of specific COX-2 inhibition in combination with chemotherapy to define toxicity and efficacy. However, as with most new therapies, phase III trials will be needed to determine whether specific COX-2 therapy is able to improve patient outcome with a reasonable safety profile.

Co-expression of vascular endothelial growth factor C (VEGF-C) and c-erbB2 in human breast carcinoma

Vascular endothelial growth factor C (VEGF-C) has angiogenic and lymphangiogenic properties and is associated with the development of lymphatic metastases in a number of epithelial malignancies. The aim of this study was to determine VEGF-C protein expression in a series of breast carcinomas and correlate this with axillary lymph node (LN) metastases, the presence of lympho-vascular invasion (LVI), bone marrow micro-metastases (BMM) and other clinico-pathological data including oestrogen receptor (ER) and c-erbB2 status. VEGF-C expression was determined by immunohistochemistry (IHC) in 51 tumours. ER and c-erbB2 were also assessed by IHC. Bone marrow analysis was performed using a combination of immunomagnetic separation and immunocytochemistry. Overall, 30/51 (59%) of the tumours were positive for VEGF-C. There was no significant correlation between VEGF-C expression and LN status, LVI, BMM, tumour size, grade or ER status. However, there was an association between c-erbB2 and VEGF-C expression (P=0.013). The correlation between VEGF-C and c-erbB2 suggests a functional relationship and may, in part, explain the aggressive phenotype associated with c-erbB2-positive tumours.

Vascular endothelial growth factor in node-positive breast cancer patients treated with adjuvant tamoxifen

In 212 postmenopausal women with node-positive oestrogen receptor-positive (ER(LBA)) breast cancer subjected to radical surgery and adjuvant tamoxifen, the risk of 6-year relapse increased with increasing values of intratumoral vascular endothelial growth factor (VEGF) in patients whose tumours had a low/intermediate ER(LBA) content compared to patients with high-ER(LBA) tumours. These findings indicate that tumour progression, activated or sustained by high VEGF levels, may be counteracted in high-ER(LBA) cancers by tamoxifen, which in contrast fails to contrast the metastatic potential in low-ER(LBA) tumours.

Structural elements of kallistatin required for inhibition of angiogenesis

Kallistatin is a serpin first identified as a specific inhibitor of tissue kallikrein. Our recent studies showed that kallikrein promoted angiogenesis, whereas kallistatin inhibited angiogenesis and tumor growth. This study is aimed to identify the structural elements of kallistatin essential for its antiangiogenic function. Kallistatin mutants at the hinge region (A377T) and a major heparin-binding domain (K312A/K313A) were created by site-directed mutagenesis. Recombinant kallistatin mutant A377T did not bind or inhibit tissue kallikrein activity. Wild-type kallistatin and kallistatin mutant A377T, but not kallistatin mutant K312A/K313A lacking heparin-binding activity, inhibited VEGF-induced proliferation, growth, and migration of human microvascular endothelial cells. Similarly, wild-type kallistatin and kallistatin mutant A337T, but not kallistatin mutant K312A/K313A, significantly inhibited VEGF-induced capillary tube formation of cultured endothelial cells in Matrigel and capillary formation in Matrigel implants in mice. To elucidate the role of the heparin-binding domain in modulating angiogenesis, we showed that wild-type kallistatin interrupted the binding of (125)I-labeled VEGF to endothelial cells, whereas kallistatin mutant K312A/K313A did not interfere with VEGF binding. Consequently, wild-type kallistatin, but not kallistatin mutant K312A/K313A, suppressed VEGF-induced phosphorylation of Akt. Taken together, these results indicate that the heparin-binding domain, but not the reactive site loop of kallistatin, is essential for inhibiting VEGF-induced angiogenesis.

Microvessel density and vascular endothelial growth factor expression in infiltrating lobular mammary carcinoma

Angiogenesis is an important prognostic factor in infiltrating ductal carcinoma (IDC). Vascular endothelial growth factor (VEGF) stimulates angiogenesis in vivo. VEGF expression has been correlated with high vascularity in IDC. However, little is known about the prognostic significance of microvessel density (MVD) and its correlation with the expression of VEGF in infiltrating lobular carcinoma (ILC). We analyzed tumor samples from 51 patients with primary classic ILC to determine the relationship between tumoral MVD and VEGF expression. Cases of pleomorphic lobular carcinoma and tubulolobular carcinoma were excluded. Five-micron thick sections obtained from formalin-fixed, paraffin-embedded tissue blocks were immunostained with antibodies to factor VIII-related antigen (Dako, Carpenteria, CA) and VEGF (Calbiochem, Boston, MA). The former was used for MVD analysis. The vessel counts from the three most vascular fields (x200 magnification) were recorded and the highest of the vessel counts of the three fields was designated as the MVD. The intensity of VEGF staining and the proportion of cells staining were scored. Both the vessel counts and the scoring of VEGF staining were evaluated by two independent pathologists. The Student's t-test and Wilcoxon rank sum test were used to compare mean MVD and VEGF scores according to various clinical and pathologic features. All significance tests were two-sided with an alpha-level of 0.05. There was good correlation between the MVD of each observer (correlation coefficient 0.775, p < 0.001). There was no correlation of MVD or VEGF score with the size or stage of the tumor. In addition, the MVD or VEGF score was not significantly different between axillary lymph node-positive cases and node-negative cases, between patients with recurrence and those without, and between patients who survived and those who died of disease. There was, however, a weak negative correlation between the MVD and VEGF expression (Spearman correlation coefficient -0.08). Neither MVD or VEGF immunoscore were associated with tumor recurrence or vital status in patients with ILC. The absence of a statistically significant positive correlation between MVD and VEGF expression suggests that other factors may play a more important role in the angiogenesis of ILC.

Vascular endothelial growth factor and oxidative damage in cancer

OBJECTIVES

VEGF may be an indicator for the angiogenic potential of a tumor and stimulates NO which plays complex roles in cancer. In our study, we investigated the levels of MDA, NO and VEGF in the plasma of various types cancer patients (untreated, yet).

DESIGN AND METHODS

The level of VEGF was determined by using ELISA. Plasma MDA, NO and VEGF levels were measured in 45 patients with various cancer types and in 21 healthy subjects.

RESULTS

Plasma MDA and VEGF levels were significantly higher than those of the healthy subjects (p < 0,0001). NO levels of the patients were significantly lower vs. the healthy subjects (p < 0,001).

CONCLUSIONS

Increased plasma VEGF and MDA concentrations and decreased plasma NO levels have been found in patients with various types of human cancer. Howewer, the prognostic and clinical significance of plasma VEGF in cancer patients is unknown.

A high cytosol value of urokinase-type plasminogen activator (uPA) may be predictive of early relapse in primary breast cancer

BACKGROUND

There is now much data that suggest a relationship between angiogenesis and breast cancer prognosis. Angiogenesis is a multistep process resulting from an ordered set of events and regulated by positive and negative modulators of microvessels growth and by the expression of various proteolytic enzymes.

MATERIALS AND METHODS

We prospectively evaluated VEGF and microvessels density on tumor specimen and cytosolic levels of uPA and PAI-1.

RESULTS

We enrolled 81 primary breast cancer patients. The median follow-up was 38 months. Using the median value as cutoff for the statistical analysis, we found significant correlation between cytosolic levels of uPA and PAI-1 (r = 0.61; p < .0001), between VEGF and steroid hormone receptor status (p = .01), between PAI-1 and tumor grading (p = .009), and between uPA and tumor size greater than 1 cm (p = .04). With respect to the prognosis, we observed a significant correlation between low uPA levels and RFS and an unforeseen, direct correlation between high VEGF values and better RFS.

CONCLUSIONS

Our preliminary results indicate that the cytosolic level of uPA at diagnosis may be predictive of early relapse in primary breast cancer.

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.

A critical review of vascular endothelial growth factor (VEGF) analysis in peripheral blood: is the current literature meaningful?

Vascular endothelial growth factor (VEGF) is a potent angiogenic growth factor with a key role in many physiological and pathological processes. Investigation into the implications of circulating levels of this cytokine is progressing at an exponential rate. However, there are important inconsistencies between reports ranging from method of sample collection, processing, software manipulation and data interpretation and controversy as to whether plasma, serum or whole blood will provide the best prognostic information. Different techniques of centrifugation and temperature on sample handling and the impact of in vitro collection of blood on subsequent VEGF results have not been fully appreciated. We provide a critical review of the literature, report the results of our further investigations, suggest a uniform protocol for handling blood samples and highlight previously unsuspected problems in data interpretation.

Prognostic and predictive indicators in operable breast cancer

Because of its biological heterogeneity and wide spectrum of responsiveness to different treatments, breast cancer is a complex disease of difficult clinical management. Over the past several years, knowledge of the molecular mechanisms regulating normal and aberrant cell growth leading to cancer has been enhanced. These advances have enabled the identification of an increasing number of surrogate biomarkers, which have been correlated with prognosis or used as predictors of response to specific treatments. Axillary nodal status, age, tumor size, pathologic grade, and hormone receptor status are the established prognostic and/or predictive factors for selection of adjuvant treatments. The role of new biomarkers, such as p53, HER2/neu, angiogenesis, and the proliferation index value, is promising; however, the clinical value of their determination must be provided by prospective clinical studies.

Expression and prognostic relevance of vascular endothelial growth factor (VEGF) and its receptor (FLT-1) in nephroblastoma

AIMS

To investigate the prognostic relevance of vascular endothelial growth factor (VEGF) and its receptor Flt-1 in nephroblastoma and whether tumour microvessel density (MVD) immunoreactivity, determined by the CD31 antigen, is related to the expression of VEGF and Flt-1.

METHODS

The expression of VEGF and Flt-1 and MVD were investigated by means of immunohistochemical analysis in 62 Wilms's tumours. Patients were treated preoperatively with chemotherapy and had a mean follow up of 5.7 years.

RESULTS

In general, VEGF and Flt-1 were expressed in normal kidney parenchyma and to a variable extent in the three main components of Wilms's tumour, namely: the blastemal, epithelial, and stromal cells. In tumour tissue, 52% and 47% of blastemal cells were positive for VEGF and Flt-1, respectively. A non-significant correlation was found between the expression of VEGF and Flt-1 in blastemal and epithelial cells and the clinicopathological stage. MVD was significantly higher in VEGF and Flt-1 positive tumours than in VEGF and Flt-1 negative tumours. Univariate analysis showed that the expression of VEGF and Flt-1 in blastemal cells was indicative of clinical progression and tumour specific survival. In addition, MVD expression was indicative of clinical progression. Epithelial staining was of no prognostic value. In a multivariate analysis, VEGF protein expression by blastemal cells was an independent prognostic marker for clinical progression.

CONCLUSIONS

These results indicate that VEGF and Flt-1 protein expression are closely related to MVD and seem to be an important predictor for poor prognosis in treated patients with Wilms's tumour. Therefore, the expression of these molecules in primary Wilms's tumour may be useful in identifying those patients at high risk of tumour recurrence and in guiding antiangiogenic treatment.

Growth regulatory factors and signalling proteins in testicular germ cell tumours

The molecular basis of testicular germ cell tumourigenesis are not well elucidated. Growth factors regulate cell growth, differentiation and apoptosis. Major families of growth factors are present in the male gonad from early fetal development to adult life. They are involved in germ cell proliferation and differentiation. Growth signalling pathways suffer deregulation in many human malignancies. Given the importance of growth signals in normal testicular development and their acquired deregulation in most human cancers, growth factors and signalling molecules that have been implicated in the genesis of testicular germ cell tumours, are reviewed. We detected a somatic mutation of SMAD4 gene, responsible for loss of protein function in seminomas. This mutational inactivation may affect the activity of several members of TGFbeta superfamily (TGFbeta, activin, inhibin, BMP). VEGF expression has been shown to predict metastasis in seminomas. A significant association of HST-1 expression, a member of fibroblast growth factors, with the nonseminomatous phenotype and with tumour stage has been described. In contrast, C-KIT is expressed by seminomas only, from the preinvasive stage. Despite intense expression in almost all seminomas, activating mutation of C-KIT gene is seldom reported. Recently, the first animal model of classical testicular seminoma has been identified in transgenic mouse overexpressing GDNF. RET (GDNF receptor) expression is demonstrated in human seminomas, and not in nonseminomatous tumours. However, the exact molecular alterations of GDNF/RET/GFRalpha1 complex in germ cell tumours are not known. Finally, beside growth factors, other signalling molecules such as peptide hormones may be involved in testicular carcinogenesis. We have demonstrated a specific pattern of somatostatin receptors expression in each type of testicular germ cell tumours, with a loss of sst3 and sst4 in seminomas and loss of sst4 and expression of sst1 in nonseminomas only. These data suggest an antiproliferative action of somatostatin in testicular cancers. In summary, many growth factors and signalling molecules seem to represent specific markers for different histological types of germ cell tumours (seminomas versus nonseminomas) and may play a role in the differentiation of germ cell tumours. Despite a complex signalling pathway involved in the physiological functions of male gonad, little is known about the implication of this signalling network in testicular malignancies. From a practical stand-point, further studies on the role of growth factors in human germ cell tumours may offer a new therapeutical perspective with the development of specific pharmacological signalling modulators that could be used as therapeutic agents.

Assessment of highly angiogenic and disseminated in the peripheral blood disease in breast cancer patients predicts for resistance to adjuvant chemotherapy and early relapse

The assessment of tumor molecular features in combination with the detection of occult malignant cells may provide important clinical information, beyond the standard staging of breast cancer. Using a nested RT-PCR technique, we assessed prospectively the presence of cytokeratin-19 (CK19) mRNA positive cells in the blood of 100 operated patients with breast cancer before the initiation of adjuvant chemotherapy and local radiotherapy. Tissue samples were prospectively collected and analyzed for estrogen (ER) and progesterone (PgR) receptor, c-erbB-2 overexpression, mutant-p53 and bcl-2 protein accumulation, proliferation index and microvessel density (MVD). CK-19 mRNA-positive cells were detected in the peripheral blood of 33% of patients. Simultaneous display of high intratumoral MVD and of CK-19 mRNA-positive cells, which characterized highly angiogenic and disseminated in the peripheral blood (HAD) disease was noted in 25% of patients. Detection of CK-19 positive cells was significantly associated with increased MVD (p = 0.002). In univariate analysis (median follow-up 30 months) CK19 mRNA detection and MVD were the most significant factors related to a short relapse-free survival (RFS), (p < 0.0001). In multivariate analysis, CK19 positivity, high MVD and c-erbB-2 overexpression were the only significant and independent variables associated with relapse (p = 0.0005, 0.03 and 0.04, respectively). Patients with HAD had an expected relapse rate close to 70% vs. <5% in the remaining patients irrespectively of the used chemotherapy regimen. The simultaneous presence of high MVD and CK19-positive cells in the blood of patients with early breast is linked with poor prognosis, which cannot be improved with standard chemotherapy regimens.

Cartilage-specific matrix protein, chondromodulin-I (ChM-I), is a strong angio-inhibitor in endochondral ossification of human neonatal vertebral tissues in vivo: relationship with angiogenic factors in the cartilage

Although cartilage contains many angiogenic factors during endochondral ossification, it is an avascular tissue. The cartilage-specific non-collagenous matrix protein chondromodulin-I (ChM-I) has been shown to be a strong angio-inhibitor. To elucidate whether ChM-I plays an essential role in angio-inhibition during endochondral ossification in man, we investigated the expression and localization of ChM-I in comparison with those of angiogenic factors and the endothelial cell marker CD34 in human neonatal vertebral tissues. Although invasion of CD34-positive endothelial cells was observed in primary subchondral spongiosa, expression of the marker of endothelial cells, CD34, was not found in neonatal vertebral cartilage matrix. Type II collagen was deposited in all matrices during endochondral ossification, whereas aggrecan was deposited in the matrix of hypertrophic cartilage, especially around lacunae. Vascular endothelial growth factor (VEGF), which is known to be a strong angiogenic factor, was localized in chondrocytes in mature to hypertrophic cartilage and also in bone marrow. Fibroblast growth factor-2 (FGF-2; basic fibroblast growth factor), which is also known to be a strong angiogenic factor, was localized in the cytoplasm of chondrocytes of mature cartilage in human vertebral cartilage tissues. Transforming growth factor (TGF)-beta has been reported to have many functions including angiogenesis, and TGF-beta1 was also localized in mature chondrocytes in endochondral tissues undergoing ossification. On the other hand, the novel cartilage-specific matrix protein ChM-I was localized in interterritorial regions of the matrix in mature to hypertrophic cartilage, especially around lacunae. In conclusion, these observations indicate that ChM-I may serve as a barrier against the angiogenic properties of VEGF, FGF-2 and TGF-beta1 during endochondral ossification, and this matrix molecule may play an essential role in determining the avascular nature of cartilage in vivo.

VEGF-mediated angiogenesis of human pheochromocytomas is associated to malignancy and inhibited by anti-VEGF antibodies in experimental tumors

BACKGROUND

Pheochromocytomas are well-vascularized tumors of the adrenal medulla. In human pheochromocytomas, angiogenesis has been associated with tumor progression. The mechanisms, however, are unknown.

METHODS

Surgical specimens of benign, invasive, and metastatic human pheochromocytomas (n = 10/5/5) were immunostained for vascular endothelial growth factor (VEGF) and CD34, to determine VEGF expression and microvessel density (vascular surface density, [VSD]). In PC12-pheochromocytoma cells, VEGF messenger RNA and protein were analyzed by Northern blotting and enzyme immunoassay; biologic activity by human umbilical vein endothelial cell-proliferation assay. Inhibition of angiogenesis of PC12 xenografts by 2 neutralizing anti-VEGF antibodies (C20-pAB, M461-mAB) was evaluated by VEGF expression, VSD, and mitotic activity.

RESULTS

VEGF expression and VSD were significantly higher in metastatic pheochromocytomas (VEGF 37.1 +/- 10.9% vs 20.7 +/- 9%, VSD 26.2 +/- 8 vs 13.5 +/- 3.3 1/mm). VEGF messenger RNA and protein were confirmed in PC12 cells and stimulated by nerve growth factor. Conditioned PC12 medium increased human umbilical vein endothelial cell proliferation more than 2-fold. Xentrotransplanted PC12 cells had marked VEGF expression and angiogenesis, which was inhibited by anti-VEGF antibodies (VEGF-expression by 29 and 38%, VSD by 43 and 46%, P <.05).

CONCLUSION

Higher VEGF expression and microvessel density in malignant pheochromocytomas suggest VEGF-mediated angiogenesis to be related to tumor progression. Angiogenesis of PC12 xenografts is mediated by VEGF. Neutralizing anti-VEGF antibodies inhibit angiogenesis in experimental pheochromocytomas and may have potential for treating nonresectable pheochromocytomas.

Expression of vascular endothelial growth factor in invasive ductal carcinoma of the breast and the relation to angiogenesis and p53 and HER-2/neu protein expression

The vascular endothelial growth factor (VEGF) appears to play an important role in tumor angiogenesis. The p53 and HER-2/neu genes have been thought to regulate VEGF expression. Although the most common genetic alterations described in human breast cancer are p53 gene mutations and HER-2/neu gene amplification, there is a paucity of reports concerning a possible association between VEGF expression and p53 and HER-2/neu expression. Ninety-nine invasive ductal carcinoma cases were examined by immunohistochemical studies with anti-VEGF, anti-p53, anti-HER-2/neu, and anti-CD34 antibodies. Computerized image analysis was used to evaluate the microvessel density (MVD). Eighty-eight tumors (88.9%) were classified as being VEGF positive. Twenty-five tumors (25.3%) showed p53 protein expression, while 36 tumors (35.4%) expressed the HER-2/neu protein. The MVD ranged from 22.0 to 197.0, with a median value of 58.5 (65.4 +/- 27.9). The tumors expressing VEGF had a significantly higher MVD than those that did not (P < 0.05). VEGF expression was significantly associated with p53 protein expression (P < 0.01). In double VEGF and p53 immunohistochemical stained sections, the two markers were generally expressed in the same tumor cells. The cancer stage was the only independent prognostic factor of disease-free and overall survival. The authors' results suggest that VEGF expression plays a role in promoting angiogenesis in invasive ductal carcinoma of the breast, and p53 is likely to be involved in regulating VEGF expression.

The anti-tumour activity of bisphosphonates

Bisphosphonates are stable analogues of pyrophosphate (PPi), an endogenous regulator of bone mineralisation. A number of placebo-controlled trials have demonstrated their positive impact on skeletal-related events (SRE) that occur as a consequence of metastatic or myelomatous bone disease. Based upon their chemical structure bisphosphonates can be classified into nitrogen-containing bisphosphonates, (N-bisphosphonates) (for example zoledronate and pamidronate) and non-nitrogen containing (for example, clodronate and etidronate), which more closely resemble PPi. Clinical trials investigating bisphosphonates in the preventative setting have shown bisphosphonates to not only delay occurrence of bone metastases in certain cancers, but in one trial, occurrence of non-osseous lesions was delayed, and survival was prolonged. Other trials however have shown the opposite. Likewise, in animal models of cancer and metastases, conflicting results have been obtained. In vitro work has concentrated on bisphosphonates direct action upon tumour cells and has found a variety of anti-tumour effects such as apoptosis induction, inhibition of cell growth, inhibition of invasive behaviour and inhibition of angiogenic factors. Furthermore it would appear that bisphosphonates have the potential to enhance anti-tumour activity of known cytotoxic drugs. Ongoing research aims to assess this further, in addition to determining more precisely the role of adjuvant bisphosphonates in cancers such as breast and prostate cancer.

Inhibitors of the vascular endothelial growth factor receptor

The inhibitors of VEGF-mediated signaling continue to wind their way through extensive preclinical and clinical development paths. Whereas the first phase III trial did not meet its endpoints, one hopes that the others will. As we learn more about the VEGF pathways in the laboratory and the clinic, we can interpret with greater certainty what role these drugs or their successors will have in the treatment of human cancers.

The prognostic value of vascular endothelial growth factor in 574 node-negative breast cancer patients who did not receive adjuvant systemic therapy

The growth and metastasising capacity of solid tumours are dependent on angiogenesis. Vascular endothelial growth factor is a mediator of angiogenesis. In this study we investigated whether vascular endothelial growth factor is associated with the natural course of the disease in primary invasive breast cancer. In 574 tumours of patients with node-negative invasive breast cancer the cytosolic levels of vascular endothelial growth factor were measured using a quantitative enzyme-linked immunosorbent assay. These patients did not receive adjuvant systemic therapy and were followed for a median follow-up time of 61 months (range 2-155 months) after the primary diagnosis. Correlations with well-known prognostic factors, and univariate and multivariate survival analyses were performed. Vascular endothelial growth factor level was positively associated with age and tumour size (P=0.042 and P=0.029, respectively). In addition, vascular endothelial growth factor level was inversely, but weakly correlated with progesterone receptor levels (PgR) (r(s)=-0.090, P=0.035). A high vascular endothelial growth factor level (equal or above the median level of 0.53 ng mg(-1) protein) predicted a reduced relapse-free survival and overall survival in the univariate survival rate analysis (for both P=0.005). In the multivariate analysis as well, vascular endothelial growth factor showed to be an independent predictor of poor relapse-free survival and overall survival (P=0.045 and P=0.029, respectively), in addition to age, tumour size and PgR. The results show that cytosolic levels of vascular endothelial growth factor in tumour tissue samples are independently indicative of prognosis for patients with node-negative breast cancer who were not treated with adjuvant systemic therapy. This implies that vascular endothelial growth factor is related with the natural course of breast cancer progression.

Angiogenesis, thrombospondin, and ductal carcinoma in situ of the breast

Angiogenesis, the growth of new vessels from existing vasculature, plays an essential role in tumour development. The process involves interaction between a variety of cells, growth factors, and components of the extracellular matrix, regulated by pro-angiogenic and anti-angiogenic factors. This review profiles these factors, outlines the available methods for measuring new vessel formation, and discusses the importance of angiogenesis in breast cancer, with emphasis on ductal carcinoma in situ.

Chemoprevention of breast cancer: implications for postmenopausal women

Estrogen administration is associated with reduction in perimenopausal symptoms and the risk for several conditions affecting postmenopausal women. As estrogen administration also increases the risk for breast cancer, a common dilemma facing many women and their physicians is whether to use estrogen replacement therapy (ERT), a selective estrogen receptor modulator (SERM) that antagonises estrogenic effects in breast tissue but retains some estrogen agonist properties in other organs, or neither. For women with average to moderate risk of breast cancer and with perimenopausal symptoms, ERT may be the best short-term choice. For very high-risk women (>1% per year) with menopausal symptoms, alternatives to ERT might be offered and tried first. A diagnosis of ductal carcinoma in situ or invasive breast cancer within the last 2 to 5 years should be considered a relative contraindication for ERT unless the tumour was estrogen receptor negative. High-risk women without menopausal symptoms are the best candidates for the only currently approved drug for breast cancer risk reduction, tamoxifen. Although the drug is approved for women with a 5-year risk of breast cancer > or = 1.7% (0.34% per year), postmenopausal women most likely to experience a favourable benefit/risk ratio are those with a Gail estimated risk of >0.5% per year without a uterus or >1% per year if they retain their uterus. Tamoxifen should not be used in women with prior history of thromboembolic or precancerous uterine conditions. Tamoxifen is often used in Europe in conjunction with transdermal ERT in hysterectomised women without obvious loss of efficacy or increased risk of thromboembolism. Raloxifene is a second generation SERM with estrogen-like agonist effects on bone but with less uterine estrogen agonist activity than tamoxifen. Raloxifene may have less potent breast antiestrogenic effects than tamoxifen, particularly in a moderate- to high-estrogen environment. Raloxifene is approved for use in reducing risk of osteoporosis, but not breast cancer. Whether it is as effective as tamoxifen in reducing breast cancer risk in postmenopausal women is the subject of a current trial. All women regardless of breast cancer risk are advised to employ nonpharmacological risk reduction measures, including normalisation of bodyweight, exercise, adequate calcium and vitamin D intake, and avoidance of smoking and alcohol. The preventive options are best weighed during an individualised consultation where a woman's menopausal symptoms and risk for breast cancer and other diseases can be examined, and the options for improving postmenopausal health can be discussed.

Inhibition of progesterone-induced VEGF production in human breast cancer cells by the pure antiestrogen ICI 182,780

The 'pure' antiestrogen ICI 182,780 (Faslodex) is in clinical trials for treatment of human breast cancer. Recently, we showed that ICI 182,780 exhibits a novel antiprogestin activity in transient transfection assays in the total absence of estrogen receptors. In this work, we determined if ICI 182,780 displays antiprogestin activity for an endogenous progesterone responsive gene. For this purpose, we examined the effect of ICI 182,780 on progestin induction of a potent angiogenic growth factor, vascular endothelial growth factor (VEGF), in T47-D human breast cancer cells. ICI 182,780 blocks the progestin induction of VEGF at both the mRNA and protein levels in T47-D cells. The antihormone does not block progestin binding to the progesterone receptor (PR), nor does it enhance the down regulation of the endogenous PR in cells that occurs upon progestin exposure. These results establish that ICI 182,780, generally considered to be a highly selective antiestrogen, displays antiprogestin activity for an endogenous progestin-regulated gene. These observations raise the possibility that an antiprogestin activity of ICI 182,780 may contribute to the antitumor activity in a subset of human breast cancers similar to T47-D cells, by inhibiting angiogenesis secondary to blockade of VEGF induction.

Biologic approaches to the treatment of gastrointestinal malignancy

Though new agents have recently been approved for the treatment of gastrointestinal malignancies, cure rates remain low and survival times of patients short. Because of these discouraging numbers, there is a vigorous search for new agents and new strategies. This article reviews some of these strategies and the status of agents in clinical development. Though an exhaustive search is impossible and the field is changing so rapidly, the agents selected here for discussion may be considered representative of others. Discussed here are agents targeting the vascular endothelial growth factor as an example of an angiogenesis inhibitor, and agents targeting the epidermal growth factor receptor, the ras oncogene, and the immune system.

Differential effects of angiostatin, endostatin and interferon-alpha(1) gene transfer on in vivo growth of human breast cancer cells

The administration of different angiogenesis inhibitors by gene transfer has been shown to result in inhibition of tumor growth in animal tumor models, but the potency of these genes has been only partially evaluated in comparative studies to date. To identify the most effective anti-angiogenic molecule for delivery by retroviral vectors, we investigated the effects of angiostatin, endostatin and interferon(IFN)-alpha(1) gene transfer in in vivo models of breast cancer induced neovascularization and tumor growth. Moloney leukemia virus-based retroviral vectors for expression of murine angiostatin, endostatin and IFN-alpha(1) were generated, characterized, and used to transduce human breast cancer cell lines (MCF7 and MDA-MB435). Secretion of the recombinant proteins was confirmed by biological and Western blotting assays. Their production did not impair in vitro growth of these breast cancer cells nor their viability, and did not interfere with the expression of angiogenic factors. However, primary endothelial cell proliferation and migration in vitro were inhibited by supernatants of the transduced cells containing angiostatin, endostatin, and IFN-alpha(1). Stable gene transfer of the IFN-alpha(1) cDNA by retroviral vectors in both MCF7 and MDA-MB435 cells resulted in a marked and long-lasting inhibition of tumor growth in nude mice that was associated with reduced vascularization. Endostatin reduced the in vivo growth of MDA-MB435, but not MCF7 cells, despite similar levels of in vivo production, and angiostatin did not impair the in vivo growth of either cell line. These findings indicate heterogeneity in the therapeutic efficacy of angiostatic molecules delivered by viral vectors and suggest that gene therapy with IFN-alpha(1) and endostatin might be useful for treatment of breast cancer.