Is the relationship between angiogenesis and metastasis in breast cancer real?

The Prognostic Value of p53 and c-erbB-2 Expression, Proliferative Activity and Angiogenesis in Node-Negative Breast Carcinoma

Aims and background

p53, c-erbB-2 and Ki-67 protein expression and microvessel density (MVD) determined by CD34 antibody were evaluated by immunohistochemistry and their correlation with clinicopathological parameters including estrogen (ER) and progesterone (PR) receptor status and survival were investigated in patients with axillary lymph node-negative infiltrating ductal breast carcinoma.

Methods

The study population consisted of 47 patients with axillary lymph node-negative infiltrating ductal breast carcinoma.

Results

p53 and c-erbB-2 expression was detected in 36.2% and 31.9% of patients, respectively. Median Ki-67 expression was 10%. There were no statistically significant differences in the distribution of p53, Ki-67 and c-erbB-2 protein expression in relation to the age of the patients or to the size, histological grade or ER and PR status of the tumors. p53 protein expression correlated positively with c-erbB-2 and Ki-67 protein expression (P <0.05). The mean MVD was 63.65 ± 29.1 and it correlated positively with histological grade and Ki-67 expression (P <0.05). Survival analysis revealed that age, tumor size, p53 and c-erbB-2 expression and PR status had no significant prognostic impact, whereas histological grade, proliferative activity and angiogenic activity were significant prognostic factors. Although ER-positive patients had a statistically significant overall survival advantage, the difference in disease-free survival was not significant.

Conclusion

In axillary lymph node-negative breast carcinoma the histological grade and the proliferative and angiogenic activity of the tumor could be useful prognostic indicators.

Assessment of Tumor Vascularization: Immunohistochemical and Non-Invasive Methods

Growth of solid tumors beyond a certain mass is dependent on the vascular bed from pre-existing host vasculature. The process of angiogenesis is essential not only for primary tumor growth but also for metastasis. The number of microvessels within the invasive component of a primary tumor reflects the degree of tumor angiogenesis. At present the most widely used method to assess neovascularization is the quantitation of intratumoral microvessel density (IMD) by immunohistochemical methods in which specific markers for endothelial cells are employed. In this paper we analyze the different methods used to assess IMD, as well as their advantages and potential methodological pitfalls. Several studies have shown a close correlation between IMD, tumor growth and the occurrence of metastasis, suggesting that IMD is a prognostic indicator of clinical relevance. Furthermore, preliminary studies suggest that determination of angiogenesis may predict responsiveness to some forms of conventional anticancer therapy. Although the histological microvessel density technique is the current gold standard to characterize tumor angiogenesis, it may not be the ideal tool for clinical purposes because it needs to be performed on biopsy material and does not assess the functional pathways involved in the angiogenic activity of tumors. Non-invasive assessment of tumor vascularity is possible in vivo by means of Doppler sonography, dynamic contrast-enhanced magnetic resonance imaging (MRI) and positron emission tomography (PET). These methods may be preferable to histological assay because they are non-invasive, survey the entire tumor, reflect both anatomic and physiologic characteristics, and may be useful to monitor the activity of antiangiogenic therapies.

Assessing Tumor Angiogenesis in Histological Samples

Tumor neovascularization acquires their vessels through a number of processes including angiogenesis, vasculogenesis, vascular remodeling, intussusception, and possibly vascular mimicry in certain tumors. The end result of the tumor vasculature has been quantified by counting the number of immunohistochemically identified microvessels in areas of maximal vascularity, so-called hot spot. Other techniques have been developed such as Chalkley counting and the use of image analysis systems that are robust and reproducible as well as being more objective. Many of the molecular pathways that govern tumor neovascularization have been identified and many reagents are now available to study these tissue sections. These include angiogenic growth factors and their receptors and cell adhesion molecules, proteases, and markers of activated, proliferating, cytokine-stimulated, or angiogenic vessels, such as CD105. It is also possible to differentiate quiescent from active vessels. Other reagents that can identify proteins involved in microenvironmental influences such as hypoxia have also been generated. Although the histological assessment of tumor vascularity is used mostly in the research context, it may also have clinical applications if appropriate methodology and trained observers perform the studies.

Angiogenesis in Paget's Disease of the Vulva and the Breast: Correlation with Microvessel Density

Our understanding of the pathogenesis of Paget's disease of the vulva and the breast remains limited. Current evidence supports the fact that angiogenesis plays an important role in the pathogenesis of several diseases. Therefore, we sought to define its role, as correlated with microvessel density, in Paget's disease of the vulva and the breast. Microvessels were analysed using anti-von Willebrand factor antibody in 105 cases of Paget's disease of the vulva and the breast comprising 71 cases of Paget's disease of the vulva, including 8 cases with invasive disease, and 34 cases of Paget's disease of the breast. The latter included 12 cases with DCIS, 5 cases with both DCIS and invasive carcinoma, and 6 with carcinoma alone. Eleven cases had no underlying tumour identified. Increased microvessel density was demonstrated in Paget's disease of the breast with DCIS and with carcinoma alone compared to Paget's disease of the breast alone, P < 0.08 and P < 0.013, respectively. There were no significant differences in microvessel density in the vulval cases. Neovascularisation is an important process in the development of Paget's disease of the breast. Other biological and molecular processes are more involved in the pathogenesis of Paget's disease of the vulva.

Angiogenesis: a prognostic determinant in pancreatic cancer?

Angiogenesis has been associated with disease progression in many solid tumours, however the statement that tumours need angiogenesis to grow, invade and metastasise seems no longer applicable to all tumours or to all tumour subtypes. Prognostic studies in pancreatic cancer are conflicting. In fact, pancreatic cancer has been suggested an example of a tumour in which angiogenesis is less essential for tumour progression. The aim of the present study was therefore to measure angiogenesis in two anatomically closely related however prognostically different types of pancreatic cancer, pancreatic head and periampullary cancer, and investigate its relation with outcome. Vessels were stained by CD31 on original paraffin embedded tissue from 206 patients with microscopic radical resection (R0) of pancreatic head (n=98) or periampullary cancer (n=108). Angiogenesis was quantified by microvessel density (MVD) and measured by computerised image analysis of three randomly selected fields and investigated for associations with recurrence free survival (RFS), cancer specific survival (CSS), overall survival (OS) and conventional prognostic factors. MVD was heterogeneous both between and within tumours. A higher MVD was observed in periampullary cancers compared with pancreatic head cancers (p<.01). Furthermore, MVD was associated with lymph node involvement in pancreatic head (p=.014), but not in periampullary cancer (p=.55). Interestingly, MVD was not associated with RFS, CSS or with OS. In conclusion, angiogenesis is higher in periampullary cancer and although associated with nodal involvement in pancreatic head cancer, pancreatic cancer prognosis seems indeed angiogenesis independent.

Influence of the tumor microenvironment on angiogenesis

It is becoming increasingly recognized that the host microenvironment is essential for regulating tumor cell behavior. The cellular stromal compartment can modulate angiogenesis either directly through enhanced secretion of pro-angiogenic factors or reduced secretion of antiangiogenic factors, or indirectly by modulating the surrounding extracellular matrix. Control of angiogenesis represents a critical step in cancer progression and is a potential therapeutic target. This article focuses on the role of the tumor microenvironment in the control of angiogenesis and how dissection of the molecular interactions may enhance prognostic and predictive power and facilitate therapeutic targeting.

Advances in the genetics of endometriosis

Endometriosis is a gynecological disease characterized by implantation of endometrial tissue outside of the uterus. Early familial aggregation and twin studies noted a higher risk of endometriosis among relatives. Studies on the roles of the environment, genetics and aberrant regulation in the endometrium and endometriotic lesions of women with endometriosis suggest that endometriosis arises from the interplay between genetic variants and environmental factors. Elucidating the hereditary component has proven difficult because multiple genes seem to produce a susceptibility to developing endometriosis. Molecular techniques, including linkage and genome-wide analysis, have identified candidate genes located near known loci related to development and regulation of the female reproductive tract. As new candidate genes are discovered and hereditary pathways identified using technologies such as genome-wide analysis, the possibility of prevention and treatment becomes more tangible for millions of women affected by endometriosis. Here, we discuss the advances of genetic research in endometriosis and describe technologies that have contributed to the current understanding of the genetic variability in endometriosis, variability that includes regulatory polymorphisms in key genes.

Dkk-3 expression in the tumor endothelium: a novel prognostic marker of pancreatic adenocarcinomas

Dkk-3 is proposed to be a new specific marker for tumor endothelial cells. Here we analyzed the clinical relevance of Dkk-3 expression in pancreas adenocarcinomas and determined its role on endothelial cell growth in vitro. Microvessel density in tumor samples was immunohistochemically determined using Dkk-3 and CD31 as endothelial cell markers, respectively. Based on the median microvessel density as a cut-off point, patients were categorized into high and low microvessel density groups and a correlation with survival and clinical parameters was assessed. Moreover, the role of Dkk-3 expression on chemosensitivity of endothelial cells was analyzed. In contrast to CD31 staining, Dkk-3-positive vessels were found only in tumor tissue and Dkk-3 microvessel density significantly correlated negative with tumor grading. In survival analysis the median survival time was 7 months for patients with Dkk-3 low, and 15 months for Dkk-3 high microvessel density (P = 0.0013). Subset analysis of patients receiving gemcitabine therapy showed that overall survival was significantly decreased in Dkk-3 low tumors than in high tumors (P = 0.009). In Cox regression Dkk-3 emerged as a significant independent parameter (P = 0.024). Dkk-3 overexpression in endothelial cells resulted in significantly enhanced growth inhibition after 5-fluorouracil or gemcitabine treatment compared to control endothelial cells and cancer cell lines. Dkk-3 low microvessel density was associated with tumor progression and worse clinical outcome. Overexpression of Dkk-3 enhanced endothelial cell growth inhibition to chemotherapeutic drugs. Therefore, we suggest that Dkk-3 high microvessel density may help to select patients who may benefit from chemotherapy.

Assessing tumor angiogenesis in histological samples

Tumor neovascularization acquires vessels through a number of processes, including angiogenesis, vasculogenesis, vascular remodelling, intussusception, and possibly vascular mimicry in certain tumors. The end result of the tumor vasculature has been quantified by counting the number of immunohistochemically identified microvessels in areas of maximal vascularity so-called hot spots. Other techniques have been developed, such as Chalkley counting and the use of image analysis systems that are robust and reproducible as well as more objective. Many of the molecular pathways that govern tumor neovascularization have been identified, and many reagents are now available to study these tissue sections. These include angiogenic growth factors and their receptors, cell adhesion molecules, proteases, and markers of activated, proliferating, cytokine-stimulated, or angiogenic vessels, such as CD105. It is also possible to differentiate quiescent from active vessels. Other reagents that can identify proteins involved in microenvironmental influences such as hypoxia have also been generated. Although the histological assessment of tumor vascularity is used mostly in the research context, it may also have clinical applications if appropriate methodology and trained observers perform the studies.

Quantification of microvessels in canine lymph nodes

Quantification of microvessels in tumors is mostly based on counts of vessel profiles in tumor hot spots. Drawbacks of this method include low reproducibility and large interobserver variance, mainly as a result of individual differences in sampling of image fields for analysis. Our aim was to test an unbiased method for quantifying microvessels in healthy and tumorous lymph nodes of dogs. The endothelium of blood vessels was detected in paraffin sections by a combination of immunohistochemistry (von Willebrand factor) and lectin histochemistry (wheat germ agglutinin) in comparison with detection of basal laminae by laminin immunohistochemistry or silver impregnation. Systematic uniform random sampling of 50 image fields was performed during photo-documentation. An unbiased counting frame (area 113,600 microm(2)) was applied to each micrograph. The total area sampled from each node was 5.68 mm(2). Vessel profiles were counted according to stereological counting rules. Inter- and intraobserver variabilities were tested. The application of systematic uniform random sampling was compared with the counting of vessel profiles in hot spots. The unbiased estimate of the number of vessel profiles per unit area ranged from 100.5 +/- 44.0/mm(2) to 442.6 +/- 102.5/mm(2) in contrast to 264 +/- 72.2/mm(2) to 771.0 +/- 108.2/mm(2) in hot spots. The advantage of using systematic uniform random sampling is its reproducibility, with reasonable interobserver and low intraobserver variance. This method also allows for the possibility of using archival material, because staining quality is not limiting as it is for image analysis, and artifacts can easily be excluded. However, this method is comparatively time-consuming.

Analysis of microvessels in pancreatic cancer: by light microscopy, confocal laser scan microscopy, and electron microscopy

BACKGROUND/PURPOSE

The microvessel density (MVD) of most malignant tumors is considered to be strongly related to metastasis and prognosis. Weidner's "hot spot method" for determining MVD is in general use, but it is possible that cells other than endothelial cells will also be stained. In our previous study, no correlations were observed between MVD determined by the "hot spot method" and prognosis/metastasis. But, using the "lumen method," we found a correlation with the number of vessel structures only. In the present study, we analyzed the staining of microvessels in pancreatic cancer, using light microscopy, confocal laser scan microscopy (CLSM), and transmission electron microscopy (TEM).

METHODS

Microvessel staining of pancreatic cancer with CD34, factor VIII, and CD45 antibodies was examined in consecutive slices by light microscopy. For CLSM, freshly resected specimens were immunostained with factor VIII and fluorescein isothiocyanate. For TEM, specimens were fixed with 2.5% glutaraldehyde, treated with 1% osmium tetroxide, and embedded in epoxy resin.

RESULTS

Staining of vessels with CD34 and factor VIII antibodies appeared similar under light microscopy. However, CD34-stained consecutive slices were judged not to reveal vessel structures, and some cells stained with CD45 antibody were similar in appearance to CD34-stained cells. Under CLSM, irregular arrangements of neovascularization, consisting of many branches, were observed, but many positively stained cells not identified as vessels were also seen. Microvessels were distinctly identified under TEM, but the types of individual cells could not be determined.

CONCLUSIONS

An integrated, reproducible method for the measurement of MVD is vital. For pancreatic cancer, the "lumen method" is recommended.

Chapter 14. Measuring intratumoral microvessel density

For a tumor to grow beyond a limited volume of 1-2 mm(3), the tumor cells must not only proliferate, but they must be able to induce the growth of new capillary blood vessels from the host. As early as 1971, it was proposed that tumor growth was dependent on angiogenesis; and, that tumor cells and blood vessels composed a highly integrated ecosystem, that endothelial cells could be switched from a resting state to one of rapid growth by a diffusible signal from tumor cells, and that anti-angiogenesis may become an effective anti-cancer therapy. Indeed, now there is considerable indirect and direct evidence to show that tumor growth is angiogenesis dependent, that tumor cells can produce diffusible angiogenic regulatory molecules, and that angiogenesis inhibitors can slow or prevent tumor growth, and that angiogenesis is a relevant target for anti-cancer therapy. Measuring intratumoral microvessel density (iMVD) in vascular "hot spots" has been shown to correlate with aggressive tumor behavior. This chapter reviews the techniques available for measuring iMVD.

Targeting angiogenesis with integrative cancer therapies

An integrative approach for managing a patient with cancer should target the multiple biochemical and physiological pathways that support tumor development while minimizing normal tissue toxicity. Angiogenesis is a key process in the promotion of cancer. Many natural health products that inhibit angiogenesis also manifest other anticancer activities. The authors will focus on natural health products (NHPs) that have a high degree of antiangiogenic activity but also describe some of their many other interactions that can inhibit tumor progression and reduce the risk of metastasis. NHPs target various molecular pathways besides angiogenesis, including epidermal growth factor receptor (EGFR), the HER-2/neu gene, the cyclooxygenase-2 enzyme, the NF-kB transcription factor, the protein kinases, Bcl-2 protein, and coagulation pathways. The herbalist has access to hundreds of years of observational data on the anticancer activity of many herbs. Laboratory studies are confirming the knowledge that is already documented in traditional texts. The following herbs are traditionally used for anticancer treatment and are antiangiogenic through multiple interdependent processes that include effects on gene expression, signal processing, and enzyme activities: Artemisia annua (Chinese wormwood), Viscum album (European mistletoe), Curcuma longa (turmeric), Scutellaria baicalensis (Chinese skullcap), resveratrol and proanthocyanidin (grape seed extract), Magnolia officinalis (Chinese magnolia tree), Camellia sinensis (green tea), Ginkgo biloba, quercetin, Poria cocos, Zingiber officinale (ginger), Panax ginseng, Rabdosia rubescens (rabdosia), and Chinese destagnation herbs. Quality assurance of appropriate extracts is essential prior to embarking on clinical trials. More data are required on dose response, appropriate combinations, and potential toxicities. Given the multiple effects of these agents, their future use for cancer therapy probably lies in synergistic combinations. During active cancer therapy, they should generally be evaluated in combination with chemotherapy and radiation. In this role, they act as biological response modifiers and adaptogens, potentially enhancing the efficacy of the so-called conventional therapies. Their effectiveness may be increased when multiple agents are used in optimal combinations. New designs for trials to demonstrate activity in human subjects are required. Although controlled trials might be preferred, smaller studies with appropriate end points and surrogate markers for antiangiogenic response could help prioritize agents for the larger resource-intensive phase 3 trials.

Dynamic MR imaging of breast lesions: correlation with microvessel distribution pattern and histologic characteristics of prognosis

PURPOSE

To evaluate the association of dynamic enhancement parameters of benign and malignant breast lesions at magnetic resonance (MR) imaging with microvessel distribution and histologic prognostic tumor characteristics.

MATERIALS AND METHODS

Regional review board approval and informed consent were obtained. Surgical resection specimens of breast lesions (32 benign, 86 malignant) in 118 patients (age range, 28-86 years; mean, 58 years) who had undergone dynamic T1-weighted MR imaging of both breasts were included in the study. Different MR enhancement parameters and microvessel density (MVD) distribution were determined. In malignant lesions, TNM stage, tumor grade, proliferative activity, and hormone receptor expression were determined. Spearman correlation coefficients; Wilcoxon, Fisher exact, Kruskal Wallis, and chi(2) tests; and logistic regression analysis were used for evaluation.

RESULTS

Malignant lesions exhibited a higher ratio of microvessels in tumor periphery versus tumor center than did benign lesions (P < .0005). High vessel ratios (P = .001) and low central vessel numbers (P = .007) were associated with high tumor grade. In malignant lesions, initial enhancement ratios of periphery to center of lesion correlated with the corresponding microvessel ratios (r = 0.61). Yet, a high peripheral MVD was not associated with strong peripheral enhancement (r = -0.09). High enhancement ratios, washout rates, and early enhancement peaks were associated with unfavorable, albeit not significant, prognostic indicators. Visible rim enhancement was the most accurate prognostic enhancement criterion for estrogen receptor status (P = .007), tumor grade (P = .06), and lymph node status (P = .046). Washout was the best discriminating criterion for proliferative activity.

CONCLUSION

The different enhancement behaviors of malignant and benign breast lesions cannot be explained by MVD alone; however, a low MVD in the center of carcinoma is reflected quantitatively by a high enhancement ratio and qualitatively by rim enhancement, with an implication of adverse prognosis.

Lymphatic vessel density in the neoplastic progression of Barrett's oesophagus to adenocarcinoma

BACKGROUND

Oesophageal adenocarcinoma is an aggressive neoplasm with poor prognosis as a result of early lymph node metastasis.

AIMS

To measure lymphatic vessel density (LVD) in the neoplastic progression from Barrett's metaplasia to adenocarcinoma and determine whether LVD can predict the risk of cancer. In addition, to correlate LVD with lymph node metastasis and assess whether LVD could be used as a prognostic indicator for outcome or survival.

METHODS

LVD and microvascular density (MVD) were assessed after immunohistochemical staining of vessels in Barrett's metaplasia, dysplasia, and adenocarcinoma tissues and were correlated with clinicopathological features.

RESULTS

LVD was significantly reduced in adenocarcinoma, being half that seen in normal stomach/oesophagus or metaplasia/dysplasia. LVD did not correlate with tumour grade, stage, or clinical outcome; however, patients who had either lymph node metastasis or invasion of tumour cells into peritumorous lymphatic vessels had a significantly worse overall survival. MVD was also assessed as a prognostic marker; its increase appeared to be linked more with the development of Barrett's metaplasia than adenocarcinoma.

CONCLUSIONS

The reduction in lymphatic vessel numbers was not useful for determining disease outcome in the patient group studied. It is the entry of tumour cells into pre-existing peritumorous lymphatic vessels that confers a significantly worse overall survival.

Increased ipsilateral whole breast vascularity as measured by contrast-enhanced magnetic resonance imaging in patients with breast cancer

BACKGROUND

Tumor-induced neovessel formation identified by gadolinium-enhanced magnetic resonance imaging (MRI) is a commonly used marker for breast malignancy. The purpose of this study was to assess possible differences in whole-breast vascularity as measured by contrast-enhanced MRI in the ipsilateral and contralateral breasts of patients with unilateral breast malignancies.

METHODS

Gadolinium-enhanced MRI of the breast using a Siemens 1.0-T scanner with dedicated breast coil was performed on 22 consecutive patients with histologically confirmed unilateral breast carcinoma. Whole-breast vascularity of the breast containing the carcinoma was estimated as increased, decreased, or similar compared with the contralateral unaffected breast. Breast vascularity was then correlated to clinical factors including tumor size, histology, multifocality, nodal involvement, and patient age and menopausal status.

RESULTS

Twenty patients had infiltrating carcinomas, and 2 patients had ductal carcinoma in situ. Four were multifocal. Fifteen of 22 patients demonstrated clear evidence of increased whole-breast vascularity in the ipsilateral breast containing the primary breast cancer compared with the contralateral breast. Although there was no clear correlation between the presence of increased whole-breast vascularity in the cancer-bearing breast with tumor size, histology, grade, mammographic appearance, or patient age and menopausal status, increased vascularity was present in 3 of 4 patients with multifocal disease and in 4 of 5 patients with metastatic disease in the axillary nodes.

CONCLUSIONS

Measurable increases in whole-breast vascularity can be identified by contrast-enhanced MRI and appear with increased frequency in the cancer-bearing breast. These findings suggest that factors other than tumor size and histology may influence development of macroscopic vessels during tumor progression and may be indicative of angiogenic tumor biology.

Evaluation of tumor angiogenesis measured with microvessel density (MVD) as a prognostic indicator in nasopharyngeal carcinoma: Results of RTOG 9505

PURPOSE

The objective of this study was to evaluate tumor angiogenesis as measured by microvessel density (MVD) as an independent prognostic factor in patients with nasopharyngeal carcinoma (NPC) treated with radiotherapy alone.

METHODS AND MATERIALS

Eligible patients included those with NPC treated with radiotherapy. Paraffin blocks of the primary tumor had a hematoxylin and eosin-stained section prepared at the block face. One representative section for tumor was stained for factor VIII-related antigen using a standard immunoperoxidase staining technique. MVD was determined by light microscopy in areas of invasive tumor containing the highest numbers of capillaries and microvessels per area. Individual microvessel counts were made on a 200x field within the area of most intense tumor neovascularization. Results were expressed as the highest number of microvessels identified within any single 200x field. Using a breakpoint of MVD <60 vs. > or =60, the distributions between the two MVD groups were compared by the method of Gray. Overall survival rates were estimated by the Kaplan-Meier method and compared by the log-rank test. A multivariate Cox proportional hazard model was employed to examine the relationship between MVD and disease outcomes while adjusting for other concomitant variables.

RESULTS

One hundred sixty-six were eligible, of whom 123 had values determined for MVD. The MVD values ranged from 9 to 243 with a median of 70. In the multivariate analysis of overall survival, distant metastases, and local-regional failure, MVD did not significantly improve the model containing T stage, N stage, age, radiation dose, and World Health Organization class.

CONCLUSIONS

We found no significant differences in overall survival, time to distant metastasis, or time to local-regional failure using a breakpoint of MVD <60 vs. MVD > or =60. The study was perhaps limited by the small size of the NPC samples.

Histological quantitation of tumour angiogenesis

Tumours establish their blood supply via a number of processes in addition to angiogenesis. These include vasculogenesis, vascular remodelling, intussusception and possibly vascular mimicry in certain tumours. The mainstay of the assessment of tumour vascularity has been counting the number of immunohistochemically identified microvessels in vascular hot spots. Nevertheless, several other techniques are available, including Chalkley counting, vascular grade and the use of image analysis systems. Angiogenic activity can furthermore be assessed in histological samples by measuring the molecules involved in the establishment of the tumour vasculature, including angiogenic growth factors and their receptors, cell adhesion molecules, proteases and markers of activated, proliferating, cytokine stimulated or angiogenic vessels, such as CD105. Measuring the maturity of vessels may give an indication of the proportion of the tumour vasculature that is functional. Other reagents that can identify hypoxia-activated pathways are also being developed. The histological assessment of tumour vascularity is mainly used in the research setting but may also have applications in the clinic if appropriate methodology and trained observers perform the studies. Gene arrays may be able to provide an angiogenesis profile. Continued study into the processes involved in generating a tumour blood supply is likely to identify new markers that may be more accurate measures.

Microvascular density does not correlate with histopathology and outcome in neuroendocrine tumors of the pancreas

Microvascular density (MVD), a marker for tumor angiogenesis, has been demonstrated to have prognostic significance in various malignancies. Previous studies have demonstrated that MVD is an independent prognostic factor in pancreatic adenocarcinoma and that longer survival is associated with hypovascular tumors. The prognostic importance of MVD in pancreatic neuroendocrine tumor (NET) has not been documented. We evaluated MVD in pancreatic NET and correlated it with clinicopathologic features and patient outcome to determine whether MVD is a useful prognostic indicator for these patients. Twenty-five pancreatic NETs from our archival files resected between 1981 and 2000 were identified. The mean MVD was determined for each tumor from the 3 most vascularized 200 x fields. Clinical follow-up ranged from 1 to 19 years, with a mean of 4.9 years. At last follow-up, 6 patients were dead of disease, 10 patients were alive without disease, 4 patients were alive with disease, and 5 patients were alive with disease status unknown. Mean MVD ranged from 43 to 527 microvessels per 200 x field. MVD did not correlate with tumor size, the examined histologic parameters, or patient outcome. MVD in pancreatic NET does not correlate with the clinicohistologic features evaluated in this study or with the patient outcome and is not a useful prognostic indicator in these patients. These results suggest that factors other than the simple number of microvessels are important in determining pancreatic NET behavior. However, most tumors were highly vascular, and additional studies may be helpful to clarify further the role of vascularity and assess the utility of antiangiogenic agents in the treatment of pancreatic NET.

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.

Microvessel density as a prognostic factor in women with breast cancer: a systematic review of the literature and meta-analysis

We performed a meta-analysis of all 87 published studies linking intratumoral microvessel density (MVD), reflecting angiogenesis, to relapse-free survival (RFS) and overall survival (OS). With median MVD as cutoff, MVD impact was measured by risk ratio (RR) between the two survival distributions. Seventeen studies did not mention survival data or fit inclusion criteria. Twenty-two were multiple publications of the same series, leaving 43 independent studies (8936 patients). MVD was assessed by immunohistochemistry, using antibodies against factor VIII (27 studies; n = 5262), CD31 (10 studies; n = 2296), or CD34 (8 studies; n = 1726). MVD might be a better prognostic factor when assessed by CD31 or CD34 versus factor VIII (P = 0.11). For RFS, statistical calculations were performed in 25 studies (6501 patients). High MVD significantly predicted poor survival [RR = 1.54 for RFS and OS with the same 95% confidence interval (CI), 1.29-1.84]. Twenty-two studies analyzed separately lymph node-negative patients (n = 3580), for whom predictors of poor survival are requested. This latter meta-analysis included 15 studies for RFS (2727 patients) and 11 for OS (1926 patients). High MVD significantly predicted poor survival [RR = 1.99 for RFS (95% CI, 1.33-2.98) and RR = 1.54 for OS (95% CI, 1.01-2.33)]. Between-study variations could result from patient selection criteria, techniques to stain and count microvessels, and cutoff selection. MVD was a significant although weak prognostic factor in women with breast cancer. Standardization of MVD assessment is needed.

Microvessel density compared with the Chalkley count in a prognostic study of angiogenesis in breast cancer patients

AIMS

Evaluation of angiogenesis by intratumoral vessel profiles can be performed by different methods. The aim of this study was to investigate the prognostic value of estimates obtained by the intratumoral microvessel density (MVD) method and then to compare with corresponding estimates obtained by the Chalkley method.

METHODS AND RESULTS

A total of 330 patients treated for primary, unilateral, invasive breast carcinoma were included. The median follow-up time was 14 years and 4 months. The microvessels were immunohistochemically stained by antibodies to CD34. MVD was not significantly correlated with any clinicopathological variables. By univariate analysis, MVD showed no prognostic value with regard to recurrence-free survival (RFS) or overall survival (OS), while the Chalkley count had significant prognostic value (P < 0.0001; RFS and OS). In the Cox multivariate analysis, MVD had no prognostic impact [median HR [confidence interval (CI)] was 0.93 [0.66, 1.32] for RFS; and HR [CI] was 0.86 [0.62, 1.19] for OS], while the Chalkley count [median HR (CI) was 2.12 (1.48, 3.06) for RFS; and HR (CI) was 1.71 (1.23, 2.37) for OS] provided independent prognostic value when adjusted for age, menopausal status, axillary lymph node status, tumour size, histological grade, adjuvant systemic treatment and radiation therapy. In comparing the results obtained by MVD in our study with those from other published studies we find good agreement.

CONCLUSIONS

The Chalkley count technique seems to be preferable for estimating angiogenesis with regard to the prognostic stratification of breast cancer patients, based on its strong prognostic impact, and acceptable reproducibility.

Assessment of endothelial cell proliferation in primary breast carcinoma and its association with axillary lymph node status

The correlation between angiogenesis as assessed by endothelial cell proliferation in blood/lymphatic vessels in primary breast carcinomas, and axillary lymph-node metastasis was studied using a case-control design. Primary breast carcinomas, < 2 cm in diameter, from 26 axillary node positive patients (case), were compared with neoplasms from 45 node-negative patients (control). Vascularity, as assessed by vessel density, and endothelial cell proliferation were measured in a single tissue section using a double immunohistochemical staining technique using MIBI (Ki-67) and FVIII antibodies. No association between vascularity and node status was found (P > 0.70). Node positive breast carcinomas had, on average, significantly smaller proliferating vessels (140+/-7 microm in perimeter) in the primary lesion when compared with node negative tumours (164+/-7 microm in perimeter (P < 0.02). In addition, the frequency of relatively small vessels (less than 180 microm in perimeter) with proliferating endothelium was higher in node positive carcinomas than lymph-node negative neoplasms (P < 0.03). This association between node status and the size and frequency of blood/lymphatic vessels with proliferating endothelium in primary carcinoma may have important implications in metastasis.

Radial intratumoral increase and correlation of microvessels and proliferation in solid breast carcinoma

AIMS

To compare correlations between different morphometrically assessed measurements of tumour microvasculature and to identify those which show closest correlation with Ki67 and to examine radial intratumoral distribution of microvessels and proliferation.

METHODS AND RESULTS

Immunohistochemically defined microvessels and Ki67+ cells were quantified in sequential fields of 0.12 mm2 (x600) in four transects in each of five tumours. The total number of vessels (TNV) correlated more closely with proliferative activity than the numbers of vessels with a discernible lumen (TLV) and TNV decreased towards the centre of the tumour whereas TLV did not. A higher proliferative index (PI) was found at the periphery of the tumours. Comparison between transects through subjectively identified microvessel hot-spots and non-hot-spot transects showed similar mean, median and peak vessel counts but showed a different distribution on chi2 analysis.

CONCLUSIONS

TNV correlates most closely with PI in breast carcinomas. There is marked variation in microvessel density and PI between fields of 0.12 mm2 but there is a significant radial reduction in both from the edge towards the centre of tumours.

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.

Prognostic importance of tumor angiogenesis in breast carcinoma with adjuvant chemotherapy

Tumor angiogenesis is believed to be related to prognostic factors involved in tumor development and metastasis. Using immunohistochemical methods, we evaluated tumor angiogenesis in 42 early invasive breast cancer patients (T1-2, NO-1-2, M0). Four patients received tamoxifen, 25 patients received CAF or CA, and 15 patients received CMF as adjuvant therapy. The median follow-up was 47 (range 24-119) months. Ten patients (43.5%) in the node-positive group and 2 patients (10.5%) in the node-negative group relapsed (p = 0.019). The mean microvessel count (MVC) was 60.3 3.05 per 200x field (range: 16-95). MVCs of postmenopausal and premenopausal patients were 50.13 +/- 5.74 and 68.64 +/- 4.11, respectively, in the axillary lymph node (ALN)-negative patient group (p = 0.04). Staining was moderate to strong in 13 (68%) ALN-negative and in 17 (74%) ALN-positive patients (p > 0.05), and was also moderate to strong in 82% of premenopausal patients and in 50% of postmenopausal patients (p = 0.037). There was no significant relationship between angiogenesis and p53, nor was angiogenesis significantly associated with the patient ER status and tumor size. No significant correlations were found between OS/DFS and Factor VIII staining or p53 (log rank test, p > 0.05). Of all ALN-negative patients with increased angiogenesis, one patient of the CMF group relapsed, but no recurrence occurred in patients undergoing anthracycline-based chemotherapy (p > 0.05). On the other hand, of all ALN-positive patients with increased angiogenesis, 5/14 patients treated with anthracylcine and 2/2 CMF-treated patients relapsed (p = 0.175). Despite the statistical insignificance, anthracycline-based adjuvant chemotherapy appears to be more effective than CMF as regards relapse prevention particularly in early ALN-positive breast cancer patients with increased angiogenesis. Additional studies are necessary to demonstrate the clinical importance of angiogenesis.

Intra-tumoural microvessel density in human solid tumours

Over the last decade assessment of angiogenesis has emerged as a potentially useful biological prognostic and predictive factor in human solid tumours. With the development of highly specific endothelial markers that can be assessed in histological archival specimens, several quantitative studies have been performed in various solid tumours. The majority of published studies have shown a positive correlation between intra-tumoural microvessel density, a measure of tumour angiogenesis, and prognosis in solid tumours. A minority of studies have not demonstrated an association and this may be attributed to significant differences in the methodologies employed for sample selection, immunostaining techniques, vessel counting and statistical analysis, although a number of biological differences may account for the discrepancy. In this review we evaluate the quantification of angiogenesis by immunohistochemistry, the relationship between tumour vascularity and metastasis, and the clinicopathological studies correlating intra-tumoral microvessel density with prognosis and response to anti-cancer therapy. In view of the extensive nature of this retrospective body of data, comparative studies are needed to identify the optimum technique and endothelial antigens (activated or pan-endothelial antigens) but subsequently prospective studies that allocate treatment on the basis of microvessel density are required.

Role of expression of cell cycle inhibitor p27 and MIB-1 in predicting lymph node metastasis in male breast carcinoma

Tumor expression of the proliferation marker (MIB-1) and the cell cycle-related protein (p27) may predict the biologic behavior of various human tumors. The purpose of this study was to evaluate the role of p27 and MIB-1 expression in predicting lymph node metastasis in male breast carcinomas (MBCs). We studied 67 patients with invasive MBC who had undergone modified radical mastectomy. Pathologic lymph node status was correlated with the p27 protein and the MIB-1 proliferation index. These factors were studied immunohistologically by standard methods. Men in this study ranged from 36 to 92 years of age (mean, 63 years); 43 (64%) were T1 lesions, and 24 (36%) were T2 lesions. Twenty-nine patients (43%) had positive nodes. p27 was expressed in 43 tumors (64%) and MIB-1 in 13 tumors (19.4%). Tumors with positive p27 showed positive lymph nodes in 10 cases (23%). In contrast, p27-negative tumors had positive lymph nodes in 18 cases (75%). Tumors positive for MIB-1 show positive lymph nodes in 11 cases (85%). However, when MIB-1 was negative, only 16 patients (30%) had positive lymph nodes. Multivariate logistic regression analysis confirmed the utility of MIB-1 overexpression in predicting lymph node metastasis ( p < 0.0006). Also, decreased p27 protein expression strongly correlates with lymph node metastasis ( p < or = 0.0001). Furthermore, when p27 was negative and MIB-1 was positive, 100% of the patients had positive lymph nodes. In contrast, when p27 was positive and MIB-1 was negative, only 12% of patients had positive lymph nodes. The reduced expression of the p27 protein and the overexpression of the MIB-1 proliferation index in this study show a significant correlation in predicting lymph nodes metastasis in MBCs.

Association of angiogenesis and disease outcome in node-positive breast cancer patients treated with adjuvant cyclophosphamide, doxorubicin, and fluorouracil: a Cancer and Leukemia Group B correlative science study from protocols 8541/8869

PURPOSE

Increased microvessel density (MVD), a reflection of tumor angiogenesis, is associated with diminished relapse-free and overall survival (OS) in several subsets of breast cancer patients. However, the utility of this assay in node-positive patients treated with adjuvant cyclophosphamide, doxorubicin, and fluorouracil (CAF) has not been well studied.

PATIENTS AND METHODS

Immunostaining for factor VIII-related antigen was performed on tissue sections from a subset of node-positive patients who received one of three dose/schedule regimens of CAF during participation in Cancer and Leukemia Group B protocol 8541. Sections from 577 cancers exhibited acceptable tumor and immunostaining quality and were included in the study. Each section was examined quantitatively for MVD as well as non-quantitatively by scoring the presence or absence of a prominent vascular pattern.

RESULTS

MVD counts were not associated with relapse-free or OS in univariate analysis. The presence of a prominent plexiform vascular pattern was correlated with decreased OS (P =.0085) in univariate analysis, but this pattern was not an independent prognostic indicator of survival in multivariate analysis. No apparent clinically important interactions between measures of angiogenesis, other prognostic factors, administration of tamoxifen, and chemotherapy dose were observed.

CONCLUSION

Assessment of angiogenesis does not provide useful information regarding prognosis in node-positive breast cancer patients treated with adjuvant CAF, nor do these measures predict which patients will benefit from dose intensification or addition of tamoxifen.

Angiogenesis in invasive breast carcinoma--a prospective study of tumour heterogeneity

Assessment of angiogenesis has been reported to be an independent prognostic factor in breast cancer, while other studies have been negative. This study prospectively investigates the degree of intratumoral microvessel heterogeneity and the possible influence on the results. From 21 invasive breast cancers six 4 micro sections were cut. Sections (n=126) were stained immunohistochemically with a CD31 monoclonal antibody (JC70). In each section, three areas with the most intense neovascularisation (hot spots) were identified and the microvessel density (MVD) was obtained by counting vessels at 200x magnification. The variation between sections contributed more to the total variance than variation between different tumours: 45.0 and 37.3%, respectively, according to a nested ANOVA analysis. Paired comparisons of two sections at a time from the same tumour showed a concordance in 59.0% (95% Confidence Interval (CI): (55.3-62.8)) with reference to a tentative cut-off level. Our study demonstrates that assessment of MVD in hot spots is questionable to measure angiogenesis due to the considerable intratumoral heterogeneity.

Angiogenesis as a predictor of long-term survival for 377 Japanese patients with breast cancer

Angiogenesis. as assessed by microvessels, has been a common prognostic indicator for breast cancer in the last decade. However, the significance of angiogenesis remains controversial. This is a retrospective study of 377 Japanese patients selected from 663 breast cancer patients operated on between 1971 and 1987. To evaluate an objective method to quantify microvessel density in angiogenesis, we employed average microvessel count (AMC) per square millimeter. We investigated five factors: angiogenesis, lymph-node status (n), clinical tumor size (T), histological grade (HG). and tumor necrosis (TN), followed for a median of 10 years. Sixty-seven patients (17.8%) had recurrence and 54 patients (14.3%) died of breast cancer. Univariate analysis showed that n, T, HG. and AMC (P = 0.0020) were significantly predictive of 20-year relapse-free survival (RFS). n, T, and HG were significantly associated with 20-year overall survival (OS) but AMC was borderline significant (P = 0.0630). Multivariate analysis for RFS and OS showed that n. T. HG, and AMC (P < 0.0001, P = 0.0033, respectively) were all significant and independent prognostic factors. When stratified by T or n, a significant impact of AMC on RFS or OS was seen both in patients with T2 and T3 carcinomas or in node-negative patients, but not in T1 or node-positive patients. Thus, we can confirm angiogenesis as a significant independent prognostic factor associated with longterm survival in Japanese breast cancer patients, especially in node-negative patients and in patients with T2 and T3 carcinomas.

Clinical significance of determination of surrogate markers of angiogenesis in breast cancer

Compelling experimental and clinical data support the concept that breast carcinoma, as most of the other solid tumors, needs to develop the angiogenic phenotype for invasiveness, progression and metastasis. Several studies have determined intratumoral microvessel density by panendothelial markers and immunohistochemical techniques, with most of them showing that the degree of vascularity is associated with prognosis of the patients operated of early-stage invasive breast cancer. More recently, certain angiogenic peptides have been assessed in human breast cancer: vascular endothelial growth factor (VEGF), platelet derived-endothelial cell growth factor (PD-ECGF, also known as thymidine phosphorylase, TP) and fibroblast growth factor family (FGFs). Among these, the most studied is VEGF, which appears to be a powerful prognostic indicator. Little data are available on the clinical significance of naturally occurring antiangiogenic factors, with few studies reporting on interleukin-12 and thrombospondins. In vivo techniques for dynamic assessment of tumor blood network are presently under extensive research, in particular for monitoring activity of inhibitors of angiogenesis. The methods of assessment of angiogenic activity and the results of published clinical studies in peer reviewed Journals with a computerized overview of literature will be presented. Overall, the results of the reported studies suggest that human breast cancer is an angiogenic-dependent tumor for which antiangiogenic therapy represents a promising novel antitumoral therapeutic strategy.

Angiogenesis and p53 protein expression in breast cancer: prognostic roles and interrelationships

The authors have analyzed, on the one hand, the prognostic impact of microvessel density (MVD) and p53 protein expression in patients with breast cancer, and on the other hand, the correlation between the microvascular pattern and the p53 protein expression. Tumors from 120 patients whose paraffin-embedded tissue blocks were available were analyzed using the immunohistochemical method. MVD and p53 protein expression were correlated with histologic grade and tumor size, respectively. The patients with highly vascularized tumor (high MVD) had decreased overall survival (p = 0.04), whereas overexpressed p53 patients did not. In multivariate analysis, axillary lymph node status (p = 0.007), tumor size (p = 0.01), and MVD (p = 0.02) showed important prognostic influence on overall survival. When the simultaneous influence of MVD and p53 protein expression on survival were analyzed, no interrelationship was detected. The results demonstrate the prognostic impact of MVD on overall survival in breast cancer and no association between MVD and p53 protein expression.

Immunohistochemical measurement of tumor vascular endothelial growth factor in breast cancer. A more reliable predictor of tumor stage than microvessel density or serum vascular endothelial growth factor

Microvessel density counting is commonly proposed as a method of assessing angiogenesis. However, results have been difficult to reproduce because of many methodological inconsistencies. Vascular endothelial growth factor (VEGF), an angiogenic regulator, is also a poor prognostic indicator in breast cancer, correlating in many studies with microvessel density. In this study, VEGF and microvessel density counting were examined as methods of assessing angiogenesis in breast cancer and correlated with tumor stage. A representative tumor section was stained with anti-CD34 and anti-VEGF. Microvessel density was evaluated using the manual "hot-spot" procedure and a semiquantitative image analysis system. Serum VEGF levels were available from an additional nine patients. Results were analyzed using Kendall's tau correlation. Tumor stage correlated with tumor VEGF, but not with microvessel "hot-spot" or vessel counts. There was no correlation between scores obtained from the manual or semiquantitative methods. Serum VEGF did not correlate with either tumor VEGF or tumor stage. The prognostic importance of VEGF in invasive breast cancer is associated with tumor stage. Measurement of tumor VEGF, as an indicator of angiogenesis, is more reliable prognostically than measurement of microvessel density or serum VEGF. Routine measurement of microvessel density in breast cancer is less reliable.

Toward checkmate: biology and breast cancer therapy for the new millennium

A better understanding of the biology of breast cancer should lead to the rational development of new treatments and the ability to customize therapy for individual patients. Though promising in theory, translating advances in biological knowledge to the clinic has been difficult. Recently several areas of research have produced treatments which have entered clinical trials: three will be reviewed here. The growth of breast cancer is regulated by growth factors and their receptors; amplification or overexpression is associated with poor prognosis. As such inhibition of growth factors and/or growth factor receptors may provide an ideal therapeutic target. Herceptin binds to c-erbB-2, a member of the epidermal growth factor receptor family. Significant responses were seen in patients with c-erbB-2 overexpressing breast cancer with Herceptin administered as a single agent or in combination with chemotherapy. Herceptin was approved by the Food and Drug Administration in late 1998. Breast cancer invasion and metastasis requires degradation of the surrounding basement membrane by matrix metalloproteinases and other proteolytic enzymes. Synthetic inhibitors of these enzymes are now in clinical trials. Breast cancers must stimulate angiogenesis, the growth of new blood vessels, in order to grow beyond a few millimeters in diameter. This nascent vascular network provides another opportunity for therapy. Preclinical models support the critical role of angiogenesis and the therapeutic benefit of angiogenesis inhibition; clinical trials are underway.

Angiogenic Index: A New Method for Assessing Microvascularity in Breast Carcinoma with Possible Prognostic Implications

The quantitation of microvessels in breast cancer in sections immunolabeled for factor VIII, CD-34, or CD-31 currently is expressed as numbers of vessels/mm2. In an attempt to perform a more accurate method for counting microvessels, we determined the number of microvessels by 1,000 tumor cells (angiogenic index; AI). This new method minimizes the possible variations concerning the width of the microscopic fields, stroma/epithelium relations, and cellular tumor size. The present study compares the number of vessels determined by the traditional method (vessels/mm2) and AI in a series of 215 cases of ductal infiltrating carcinoma not otherwise specified. Also we studied the degree of correlation between both methods and with pathologic variables (tumor size, histologic grade, mitotic count, tumor necrosis, vascular invasion, skin infiltration, and axillary lymph node metastasis). Our results showed that the AI correlates more significantly than the classic microvessel density determination with other prognostic factors in breast cancer. In histologic grade III tumors, high AI correlates significantly with the presence of more than three axillary lymph nodes metastases. Therefore we recommend determining the degree of tumor angiogenesis by counting vessels per 1,000 tumor cells (AI) because of its reliable determination and significant correlation with other prognostic factors.

Vascular grading of angiogenesis: prognostic significance in breast cancer

The study aimed to evaluate the prognostic value of angiogenesis by vascular grading of primary breast tumours, and to evaluate the prognostic impact of adding the vascular grade to the Nottingham Prognostic Index (NPI). The investigation included 836 patients. The median follow-up time was 11 years and 4 months. The microvessels were immunohistochemically stained by antibodies against CD34. Angiogenesis was graded semiquantitatively by subjective scoring into three groups according to the expected number of microvessels in the most vascular tumour area. The vascular grading between observers was moderately reproduced (kappa = 0.59). Vascular grade was significantly associated with axillary node involvement, tumour size, malignancy grade, oestrogen receptor status and histological type. In univariate analyses vascular grade significantly predicted recurrence free survival and overall survival for all patients (P < 0.0001), node-negative patients (P < 0.0001) and node-positive patients (P < 0.0001). Cox multivariate regression analysis showed that vascular grading contributed with independent prognostic value in all patients (P < 0.0001). A prognostic index including the vascular grade had clinical impact for 24% of the patients, who had a shift in prognostic group, as compared to NPI, and implied a better prognostic dissemination. We concluded that the angiogenesis determined by vascular grading has independent prognostic value of clinical relevance for patients with breast cancer.

Quantification of microvessel density of breast carcinoma: an assessment of the inter- and intraobserver variation

The density profile of microvessels (MVD) has recently emerged as a prognostically independent morphological marker of various malignancies, including carcinoma of the breast. MVD-scoring may thus afford the pathologist the opportunity to identify subsets of early stage breast cancer patients, which may benefit from adjuvant therapy. Reproducibility studies are, however, mandatory. Fifty sections of invasive breast carcinoma, immunolabelled for Factor VIII-related antigen, were scored independently by two observers for the number of vessel-profiles (v-p) in the following manner: 1) 250 randomly selected high power fields (HPF) were scored by two analysts to evaluate the agreement of the counting per se; and 2) the hot spot(s), i.e. the zones considered the most vessel rich, in the 50 sections were identified and scored twice to evaluate the agreement on selecting hot spots. When the observers evaluated MVD in the very same 250 HPF a median deviation of 2 v-p (10%) was produced. The interobserver disparity was further accentuated when the participants independently had to identify the hot spots with a median deviation of 6 v-p (13%). Intraobserver variation was approximately equal to the interobserver discordance. Divergences were most conspicuous in fields with a complex vasculature. In conclusion the v-p scoring resulted in substantial inter- and intraobserver variation both in selecting hot spots and in performing the scoring per se. Alternative-scoring techniques, including strict stereological principles, should be considered in the morphological evaluation of angiogenesis.

Vascular endothelial growth factor in ovarian cancer

Tumor growth requires nutrients and oxygen. Both nutrients and oxygen are provided via the vasculature. Thus, when a tumor increases in volume, new blood vessels must form and invade the expanding tumor. This process, called angiogenesis, has theoretical significance in the context of ovarian cancer for two reasons. First, the process of angiogenesis and vessel regression occurs in a tightly controlled way as part of normal ovarian function. This suggests that at least some ovarian cells are primed to produce the paracrine stimulus needed for new blood vessel growth and that, on transformation, this capability is present early in tumor development. Second, the characteristically large size of ovarian tumors indicates that angiogenesis is mandatory to sustain the tumor. In this article, we review the experimental and clinical correlative data that support the hypothesis that ovarian cancers are highly angiogenic. Because a critical component of angiogenesis is the paracrine and autocrine production of vascular endothelial cell growth factor, there is substantial focus on this topic.

The relationship between prognostic and predictive factors in the management of breast cancer

The discovery of new prognostic factors proceeds at a much more rapid pace than our knowledge of how to properly utilize this information in the management of patients with breast cancer, especially those with early breast cancer that has not metastasized to regional lymph nodes. Prognostic factors provide information on how the patient is likely to do regardless of treatment. Predictive factors provide information on whether a patient is likely to benefit from therapy. Most factors identified to date provide prognostic information, but relatively few provide information that is truly helpful in making a therapeutic decision in the management of individual patients. In large part this is because there has been insufficient study of the factor, especially prospective evaluations of the factor. Unfortunately this has resulted in the premature use of this information under the general rubric that patients with a poor prognosis deserve more treatment in spite of the fact that there may be no benefit from that therapy in the poor prognostic group.

Fully automated microvessel counting and hot spot selection by image processing of whole tumour sections in invasive breast cancer

BACKGROUND

Manual counting of microvessels is subjective and may lead to unacceptable interobserver variability, which may explain conflicting results.

AIMS

To develop and test an automated method for microvessel counting and objective selection of the hot spot, based on image processing of whole sections, and to compare this with manual selection of a hot spot and counting of microvessels.

METHODS

Microvessels were stained by CD31 immunohistochemistry in 10 cases of invasive breast cancer. The number of microvessels was counted manually in a subjectively selected hot spot, and also in the same complete tumour sections by interactive and automated image processing methods. An algorithm identified the hot spots from microvessel maps of the whole tumour section.

RESULTS

No significant difference in manual microvessel counts was found between two observers within the same hot spot, and counts were significantly correlated. However, when the hot spot was reselected, significantly different results were found between repeated counts by the same observer. Counting all microvessels manually within the entire tumour section resulted in significantly different hot spots than manual counts in selected hot spots by the same observer. Within the entire tumour section no significant differences were found between the hot spots of the manual and automated methods using an automated microscope. The hot spot was found using an eight connective path search algorithm, was located at or near the border of the tumour, and (depending on the size of the hot spot) did not always contain the field with the largest number of microvessels.

CONCLUSIONS

The automated counting of microvessels is preferable to the manual method because of the reduction in measurement time when the complete tumour is scanned, the greater accuracy and objectivity of hot spot selection, and the possibility of visual inspection and relocation of each measurement field afterwards.

Prognostic value of vascular density and cell proliferation in breast cancer patients

We measured microvessel density and cell proliferation index in 84 breast cancers using survival analysis to find out their prognostic value. Immunohistochemistry was applied using antibody to factor VIII-related antigen as a marker for microvessels and MIB-1 antibody to stain proliferating cells. We were not able to show any difference in survival with a mean follow-up of 10.3 years between patients with high and low microvessel count or cell proliferation index. Vascular density did not correlate with the cell proliferation rate (p = 0.4). However, patient age correlated negatively with the cell proliferation index of the tumor (p = 0.0009). There was no significant difference both in microvessel count and in cell proliferation between patients with lymph node metastasis and node negative patients. This result questions the usefulness of vascular density and cell proliferation rate as prognostic markers in breast cancer.