Tumour angiogenesis in prostatic carcinoma with and without bone marrow metastasis: a morphometric study

Interplay between Prostate Cancer and Adipose Microenvironment: A Complex and Flexible Scenario

Adipose tissue is part of the prostate cancer (PCa) microenvironment not only in the periprostatic area, but also in the most frequent metastatic sites, such as bone marrow and pelvic lymph nodes. The involvement of periprostatic adipose tissue (PPAT) in the aggressiveness of PCa is strongly suggested by numerous studies. Many molecules play a role in the reciprocal interaction between adipocytes and PCa cells, including adipokines, hormones, lipids, and also lipophilic pollutants stored in adipocytes. The crosstalk has consequences not only on cancer cell growth and metastatic potential, but also on adipocytes. Although most of the molecules released by PPAT are likely to promote tumor growth and the migration of cancer cells, others, such as the adipokine adiponectin and the n-6 or n-3 polyunsaturated fatty acids (PUFAs), have been shown to have anti-tumor properties. The effects of PPAT on PCa cells might therefore depend on the balance between the pro- and anti-tumor components of PPAT. In addition, genetic and environmental factors involved in the risk and/or aggressiveness of PCa, including obesity and diet, are able to modulate the interactions between PPAT and cancer cells and their consequences on the growth and the metastatic potential of PCa.

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.

Crocetin treatment inhibits proliferation of colon cancer cells through down-regulation of genes involved in the inflammation

Background

The current study was designed to investigate the effect of crocetin on the proliferation inhibition of colon cancer cells and the underlying mechanism.

Methods

MTT assay showed inhibition of proliferation of colon cancer cells in a dose based manner by crocetin treatment. At 30 µM concentration of crocetin proliferation rate of colon cancer cells was reduced to 14% after 24 h. Flow cytometry and fluorescence microscopy revealed induction of apoptosis in colon cancer cells on treatment with crocetin. The tube formation was suppressed significantly in the cultures of HUVEC treated with 30 µM concentration of crocetin compared to the control cultures.

Results

The results from transwell assay revealed a significant reduction in the population of DU-145 cells passing through filters of transwell on treatment with crocetin compared to the control cells. Treatment of the DU-145 cells with crocetin caused a significant reduction in the expression levels of NF-κB, VEGF and MMP-9. The results from RT-PCR analysis revealed a significant reduction in the expression of genes involved in inflammation including, HMGB1, IL-6 and IL-8 on treatment of DU-145 cells with crocetin. However, the expression of NAG-1 gene was increased by crocetin treatment in DU-145 cells significantly compared to the control cells.

Conclusion

Crocetin inhibits growth of colon cancer cells and prevents tube formation through induction of apoptosis. Therefore, crocetin can be used efficiently for the treatment of colon cancer.

Review : Angiogenesis: A new target for antineoplastic therapy

Objective. To review the pathophysiologic rationale and therapeutic applications of inhibiting angiogenesis in solid tumor growth.

Data Sources. A MEDLINE search of articles published from 1985 to 1995 and a CancerLit search of articles published from 1988 to 1995, using the MESH heading "neovascularization" and text words "angiogenesis" and "antiangiogenesis." References listed in identified publications were reviewed for additional pertinent literature.

Study Selection. All human trials evaluating angiogenesis inhibitors in malignant disease and pre- clinical trials that illustrate potential mechanisms of action of such agents were included.

Data Synthesis. Angiogenesis, the formation of new blood vessels, is necessary for the development of significant solid tumor growth. Inhibition of angio genesis is a unique mechanism of antineoplastic ther apy that does not use traditional cytotoxic actions. Four investigational antiangiogenic agents are cur rently being evaluated in phase I and II trials. Poten tially beneficial applications of angiogenesis inhibitors include suppression of occult and premalignant le sions, symptomatic control of angiogenesis-depen dent malignancies, and combination therapy with traditional antineoplastic agents.

Conclusion. Inhibition of angiogenesis is a new pharmacologic strategy that may prove useful in controlling malignant growth. A number of agents with antiangiogenic activity have been developed, and further study of these drugs will define their role in antineoplastic therapy.

Kinetic Modeling Application to (18)F-fluoroethylcholine Positron Emission Tomography in Patients with Primary and Recurrent Prostate Cancer Using Two-tissue Compartmental Model

Although ¹⁸F-fludeoxyglucose-positron emission tomography (PET) is the most applied diagnostic method in tumor staging, its role in prostate cancer (PCA) is limited because glucose metabolism tends to be low unless PCA has high Gleason score. Alternatively, choline PET was introduced as a valuable imaging method. Kinetic analysis of PET acquisition has increasingly gained momentum as an investigative tool because it provides a non-invasive approach to obtain kinetic and metabolic data from tissues of interest including transport and metabolism of the administered material. In this regard, we sought to apply it in ¹⁸F-fluoroethylcholine (FECH)-PET/computed tomography (CT) in patients with PCA. 64 patients, the mean age 69 (range: 47-87 years) with primary/recurrent PCA were encompassed. They underwent ¹⁸F-FECH-PET started with a dynamic acquisition using a 20-frame each 30 s over the prostate region and followed at 1 h post-injection by a static whole body imaging. The kinetic evaluation of the data was performed using the software package PMOD (PMOD Technologies Ltd., Zürich, Switzerland). Significant increase in mean values for K1, K3, FD, standardized uptake value (SUV) and global influx in tumor tissue versus normal tissue (P < 0.05). Moderate but significant correlation (r: 0.28, P = 0.023) between SUV and K1. By contrast, no correlation between SUV and K3 (r: −0.08, P = 0.79). In patients with recurrent tumors, there is no significant difference in all kinetic parameters and SUV (P > 0.1) between the different types of recurrences. The kinetic analysis of dynamic FECH-PET provides a novel method in primary PCA diagnosis and could be of potential value in the delineation of tumor focus.

Predictive value of vascular endothelial growth factor overexpression in early relapse of colorectal cancer patients after curative resection

BACKGROUND

Preclinical and clinical studies have indicated that vascular endothelial growth factor (VEGF) is the predominant angiogenic factor. Recently, there was a consistent trend of poorer survival rates in colorectal cancer (CRC) patients of earlier relapse. The purpose of this study was to investigate novel predictors of early relapse in stage I-III CRC and further to determine their correlation with disease outcomes.

MATERIALS AND METHODS

We retrospectively analyzed clinicopathological features and VEGF expression by immunohistochemical staining in 100 stage I-III CRC patients undergoing curative resection to identify predictors of postoperative early relapse.

RESULTS

Among 100 patients, 40 patients were classified into early relapse group, and 60 patients were categorized into non-early relapse group. A multivariate logistic regression analysis showed that vascular invasion (P = 0.048), perineural invasion (P = 0.042), VEGF overexpression (P = 0.023), and high postoperative carcinoembryonic antigen (CEA) levels (P = 0.004) were independent predictors of early relapse. Additionally, we found that with more predictors such as the combined incidence of vascular invasion, perineural invasion, VEGF overexpression, and postoperative CEA levels are involved, the incidence of early postoperative relapse increases. Moreover, VEGF overexpression predicted not only early postoperative relapse but also disease-free survival (P < 0.001) and overall survival (P = 0.002).

CONCLUSIONS

This study suggests that VEGF overexpression is an important predictor of early postoperative relapse in patients with stage I-III CRC and may help identify patients who would benefit from intensive follow-up and therapeutic programs.

Nestin: A novel angiogenesis marker and possible target for tumor angiogenesis

Abnormal vasculature, termed tumor vessels, is a hallmark of solid tumors. The degree of angiogenesis is associated with tumor aggressiveness and clinical outcome. Therefore, exact quantification of tumor vessels is useful to evaluate prognosis. Furthermore, selective detection of newly formed tumor vessels within cancer tissues using specific markers raises the possibility of molecular targeted therapy via the inhibition of tumor angiogenesis. Nestin, an intermediate filament protein, is reportedly expressed in repair processes, various neoplasms, and proliferating vascular endothelial cells. Nestin expression is detected in endothelial cells of embryonic capillaries, capillaries of the corpus luteum, which replenishes itself by angiogenesis, and proliferating endothelial progenitor cells, but not in mature endothelial cells. Therefore, expression of nestin is relatively limited to proliferating vascular endothelial cells and endothelial progenitor cells. Nestin expression is also reported in blood vessels within glioblastoma, prostate cancer, colorectal cancer, and pancreatic cancer, and its expression is more specific for newly formed blood vessels than other endothelial cell markers. Nestin-positive blood vessels form smaller vessels with high proliferation activity in tumors. Knockdown of nestin in vascular endothelial cells suppresses endothelial cell growth and tumor formation ability of pancreatic cancers in vivo. Using nestin to more accurately evaluate microvessel density in cancer specimens may be a novel prognostic indicator. Furthermore, nestin-targeted therapy may suppress tumor proliferation via inhibition of angiogenesis in numerous malignancies, including pancreatic cancer. In this review article, we focus on nestin as a novel angiogenesis marker and possible therapeutic target via inhibition of tumor angiogenesis.

Perfusion CT in colorectal cancer: comparison of perfusion parameters with tumor grade and microvessel density

Objective

The purpose of this study was to prospectively compare pre-operative computed tomography (CT) perfusion parameters with tumor grade from colorectal adenocarcinoma (CRC) and to correlate pre-operative CT perfusion parameters with microvessel density (MVD) to evaluate angiogenesis in CRC.

Materials and Methods

Pre-operative perfusion CTs were performed with a 64-channel multidetector row CT in 27 patients (17 women and 10 men; age range 32-82 years) who were diagnosed with CRC involving the sigmoid and rectum between August 2006 and November 2007. All patients underwent surgery without pre-operative chemotherapy or radiation therapy. Dynamic perfusion CTs were performed for 65 seconds after intravenous injection of contrast medium (100 mL, 300 mg of iodine per mL, 5 mL/sec). Before surgery, blood flow (BF), blood volume, mean transit time (MTT), and permeability-surface area product were measured in the tumor. After surgery, one gastrointestinal pathologist evaluated tumor grade and performed immunohistochemical staining using CD 34 to determine MVD in each tumor. The Kruskal-Wallis test was used to compare CT perfusion parameters with tumor grade, and Pearson's correlation analysis was used to correlate CT perfusion parameters with MVD.

Results

In 27 patients with CRC, tumor grading was as follows: well differentiated (n = 8); moderately differentiated (n = 15); and poorly differentiated (n = 4). BF was higher in moderately differentiated CRC than well differentiated and poorly differentiated CRCs (p = 0.14). MTT was shorter in moderately differentiated than well differentiated and poorly differentiated CRCs (p = 0.039). The MVD was greater in poorly differentiated than well differentiated and moderately differentiated CRCs (p = 0.034). There was no significant correlation between other perfusion parameters and tumor grade. There was no significant correlation between CT perfusion parameters and MVD.

Conclusion

BF and MTT measurement by perfusion CT is effective in predicting moderately differentiated CRCs. However, perfusion CT is limited in distinguishing well differentiated and poorly differentiated CRCs. Pre-operative perfusion CT does not reflect the MVD of CRCs.

Nestin in gastrointestinal and other cancers: Effects on cells and tumor angiogenesis

Nestin is a class VI intermediate filament protein that was originally described as a neuronal stem cell marker during central nervous system (CNS) development, and is currently widely used in that capacity. Nestin is also expressed in non-neuronal immature or progenitor cells in normal tissues. Under pathological conditions, nestin is expressed in repair processes in the CNS, muscle, liver, and infarcted myocardium. Furthermore, increased nestin expression has been reported in various tumor cells, including CNS tumors, gastrointestinal stromal tumors, pancreatic cancer, prostate cancer, breast cancer, malignant melanoma, dermatofibrosarcoma protuberances, and thyroid tumors. Nestin is reported to correlate with aggressive growth, metastasis, and poor prognosis in some tumors; however, the roles of nestin in cancer cells have not been well characterized. Furthermore, nestin is more specifically expressed in proliferating small-sized tumor vessels in glioblastoma and gastric, colorectal, and prostate cancers than are other tumor vessel markers. These findings indicate that nestin may be a marker for newly synthesized tumor vessels and a therapeutic target for tumor angiogenesis. It has received a lot of attention recently as a cancer stem cell marker in various cancer cells including brain tumors, malignant rhabdoid tumors, and uterine, cervical, prostate, bladder, head and neck, ovarian, testicular, and pancreatic cancers. The purpose of this review is to clarify the roles of nestin in cancer cells and in tumor angiogenesis, and to examine the association between nestin and cancer stem cells. Nestin has the potential to serve as a molecular target for cancers with nestin-positive cancer cells and nestin-positive tumor vasculature.

A double-blind randomized crossover study of oral thalidomide versus placebo for androgen dependent prostate cancer treated with intermittent androgen ablation

PURPOSE

We determined whether thalidomide can prolong progression-free survival in men with biochemically recurrent prostate cancer treated with limited androgen deprivation therapy.

MATERIALS AND METHODS

A total of 159 patients were enrolled in a double-blind randomized trial to determine if thalidomide can improve the efficacy of a gonadotropin-releasing hormone agonist in hormone responsive patients with an increasing prostate specific antigen after primary definitive therapy for prostate cancer. Patients were randomized to 6 months of gonadotropin-releasing hormone agonist followed by 200 mg per day oral thalidomide or placebo (oral phase A). At the time of prostate specific antigen progression gonadotropin-releasing hormone agonist was restarted for 6 additional months. Patients were then crossed over to the opposite drug and were treated until prostate specific antigen progression (oral phase B). Testosterone and dihydroxytestosterone were likewise monitored throughout the study.

RESULTS

During oral phase A the median time to prostate specific antigen progression was 15 months for the thalidomide group compared to 9.6 months on placebo (p = 0.21). The median time to prostate specific antigen progression during oral phase B for the thalidomide group was 17.1 vs 6.6 months on placebo (p = 0.0002). No differences in time to serum testosterone normalization between the thalidomide and placebo arms were documented during oral phase A and oral phase B. Thalidomide was tolerable although dose reductions occurred in 47% (58 of 124) of patients.

CONCLUSIONS

Despite thalidomide having no effect on testosterone normalization, there was a clear effect on prostate specific antigen progression during oral phase B. This is the first study to our knowledge to demonstrate the effects of thalidomide using intermittent hormonal therapy.

Preoperative plasma endoglin levels predict biochemical progression after radical prostatectomy

PURPOSE

Endoglin (CD105) is a transmembrane glycoprotein expressed by human vascular endothelial cells thought to play a pivotal role in endothelial cell proliferation. The aim of this study was to evaluate the association of preoperative plasma endoglin levels with established clinical and pathologic features of prostate cancer and disease progression after radical prostatectomy.

EXPERIMENTAL DESIGN

Preoperative plasma endoglin levels were measured in 425 patients who underwent radical prostatectomy for clinically localized prostate cancer using a commercially available ELISA assay. Multivariate logistic regression was used to test the association of plasma endoglin levels with biochemical progression after radical prostatectomy.

RESULTS

Median follow-up for patients alive at the time of analysis was 36.8 months (interquartile range, 44.1). Of 425 patients, 77 patients (18.1%) experienced biochemical progression after radical prostatectomy. Preoperative plasma endoglin levels were significantly elevated in patients with higher preoperative total serum prostate-specific antigen (P < 0.001) and adverse pathologic features. Preoperative plasma endoglin was an independent predictor of biochemical progression after surgery after adjusting for the effects of standard preoperative and postoperative features (P < 0.001 and P = 0.026, respectively).

CONCLUSIONS

Preoperative plasma endoglin levels are associated with established features of advanced prostate cancer. More importantly, higher preoperative plasma endoglin levels are independent predictors of an increased risk of biochemical progression in patients treated with radical prostatectomy and bilateral pelvic lymphadenectomy.

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.

Angiogenic patterns and their quantitation in high grade astrocytic tumors

BACKGROUND

The objectives of this study on high grade astrocytic tumors were (i) to establish differences, if any, between grades III & IV tumors among angiogenic parameters, both qualitative and quantitative, and (ii) to correlate angiogenic parameters with proliferation indices, namely T2a and MIB1 labeling indices.

DESIGN

Twenty nine consecutive cases of WHO grades III (11) and IV (18) astrocytic tumors diagnosed in the year-2004 were studied, using H&E and CD34, MIB1 and T2a immunostaining by streptavidin biotin technique. Angiogenic patterns were studied and parameters quantitated using Image Pro Plus software (four hotspots) on CD34 immunostained sections to determine intratumoral microvessel density (iMVD), microvascular area (MVA), aspect, mean diameter (MD) and fractal dimension (FD).

RESULTS

Main angiogenic patterns of capillary (18) and glomeruloid (9) types were best developed in glioblastomas. Statistically significant differences (P<0.05) were seen between grades III and IV in iMVD, aspect, MD and FD, but not in angiogenic patterns or MVA (P = 0.27). Statistically significant differences (P<0.05) were seen between glioblastomas with glomeruloid vs. capillary types in iMVD and FD, but not in MVA, aspect and mean vessel diameter. T2a values correlated with MIB1 labeling indices (R = 0.965, P<0.001). Intratumoral endothelial MIB1 LI was significantly higher in grade IV as compared to grade III, but did not correlate with angiogenic parameters. No correlation of angiogenic patterns and proliferation indices was noted (R = -0.221, P = 0.26). Limited follow up data showed all recurrent grade IV tumors to be of glomeruloid type.

CONCLUSION

Increased angiogenesis in grade IV, as compared to grade III, astrocytic tumors is characterized by an increased number/density of vessels: an increase in vessels characterized by disproportionate lengthening and likely associated with the infiltrative properties of the tumors; and an increase in pliable, irregularly shaped or structured vessels. In addition, there is a greater frequency of glomeruloid structures indicating inadequate directional migration of the newly formed vessels. The lack of correlation of these angiogenesis parameters with the MIB1 and T2a proliferation indices reflects the complexity of angiogenesis parameters in high grade gliomas. Further studies are needed to determine the usefulness of the angiogenic parameters in the improved diagnosis (grading) and prognosis of astrocytic tumors.

The use of thalidomide in androgen-independent prostate cancer

More than 200,000 men will be diagnosed with prostate cancer during the year 2006. Approximately 20% to 30% of these cases may develop advanced disease, for which there currently is no cure. Although therapy for this disease has improved significantly over the past few years, with docetaxel treatment showing improved survival times in metastatic disease, there remains the need for improved treatment options. Dr. Folkman put forth the idea of angiogenesis in 1971, and, since that time, researchers have been trying to determine the best possible way to inhibit blood vessel formation. This review summarizes the use of thalidomide in androgen-independent prostate cancer and the results of trials conducted at the National Cancer Institute.

Altered expression of transcription factor Sp1 critically impacts the angiogenic phenotype of human gastric cancer

Our recent study has shown that transcription factor Sp1 is an independent prognostic factor in gastric cancer. However, it is unclear how Sp1 impacts gastric cancer biology. Since Sp1 regulates multiple genes important to angiogenesis, we sought to evaluate the relationship between Sp1 expression and microvessel density (MVD) as well as their effects on cancer patient survival. The expression of Sp1 and status of MVD was determined using archival tissues of 86 cases of resected human gastric cancer. We found that MVD correlated highly with Sp1 expression (P < 0.001). Patients with strong Sp1 expression were 12 times more likely to have high MVD than were those with negative Sp1 expression. In univariate survival analyses, both elevated Sp1 expression (P = 0.007) and high MVD expression (P = 0.036) were associated with inferior survival. However, when Sp1 expression, MVD expression, disease stage, completeness of resection, Lauren's classification, and patient age were entered into a Cox proportional hazards model, only strong Sp1 expression (P = 0.047) and advanced stage (P < 0.01) were independently prognostic of poor survival. Furthermore, knocking down Sp1 expression significantly impaired the angiogenic potential of tumor cells in vitro and suppressed angiogenesis in vivo animal models. Therefore, we provided both clinical and experimental evidence to indicate that Sp1 might impact gastric cancer development and progression through regulating angiogenesis, a critical aspect of cancer biology.

Antiangiogenesis: A Possible Treatment Option for Prostate Cancer?

With a need for effective treatment modalities in prostate cancer, angiogenesis is a likely target for the interference of tumor progression. Angiogenesis promotes the vasculature of a tumor, allowing for tumor progression and for cancer cells to metastasize and spread throughout the circulatory system. To date, there are > 20 antiangiogenic drugs undergoing preclinical and clinical investigation alone and in conjunction with other treatment options to determine the validity of antiangiogenic agents in the treatment of prostate cancer. This article reviews several aspects of antiangiogenesis and its relationship to the treatment of prostate cancer.

Minor inflammation after surgical evacuation compared with fibrinolytic therapy of experimental intracerebral hemorrhages

OBJECTIVES

Toxic components released from the intracerebral blood clot, such as thrombin and hemoglobin, potentially trigger brain edema formation and therefore favor an early evacuation of the clot. Despite a significant reduction in hematoma size in our porcine model of hematoma induction by injecting autologous blood ICP-controlled into the right frontal white matter with subsequent fibrinolysis using recombinant tissue-plasminogen activator (rt-PA) and aspiration of the liquefied clot (n = 9), local rt-PA promoted delayed perihematomatous edema formation and invoked a substantial inflammatory reaction compared with controls (n = 11).

METHODS

We therefore modified our formerly developed porcine model of intracerebral hemorrhage in removing the hematoma by open craniotomy and suction of the clot in seven animals. The residual hematoma size and extent of perifocal edema were evaluated over 10 days on planimetry of the MRI data, and correlated to the histopathological changes of edema and inflammation found at autopsy.

RESULTS

The edema volume on day 4 was significantly less in the surgical group compared with the lysis group (p < 0.03). On day 10, however, the difference in edema size was not statistically significant compared with the lysis group (p < 0.07) and the control group (p < 0.09). The inflammatory response was minor compared with the lysis and control group.

DISCUSSION

In conclusion, despite a significant reduction in hematoma size by surgical removal of the clot, only the inflammatory response, but not the extent of delayed edema can be positively influenced.

Expression of Autocrine Motility Factor Correlates with the Angiogenic Phenotype of and Poor Prognosis for Human Gastric Cancer

Autocrine motility factor (AMF) is a cytokine known to regulate tumor cell motility. Recent studies have extended its role to many other aspects of cancer biology. In the present study, we examined the level of AMF expression and its relationship with vascular endothelial growth factor (VEGF) expression and the angiogenic phenotype in human gastric cancer and their effect on survival. The AMF and VEGF expression level and tumor microvessel density (MVD) status in archived tissue specimens from 86 resected gastric cancer cases were determined. AMF expression was significantly higher in both primary tumors and lymph node metastases than in adjacent normal gastric mucosa and normal gastric mucosa from individuals without gastric cancer. In univariate survival analyses, strong AMF expression was associated with inferior survival (P = 0.028). In a Cox proportional hazards model, strong AMF expression (P = 0.019) was independently prognostic of poor survival. Strong AMF expression in the lymph node metastases was associated with poor survival (P = 0.011). Furthermore, AMF expression in the primary tumors was directly correlated with VEGF expression and MVD status. We found the first clinical evidence that AMF expression is directly correlated with VEGF expression and MVD status and predicts clinical outcome in patients with gastric cancer, supporting the hypothesis that the AMF/AMF receptor pathway plays an important role in multiple aspects of cancer biology.

Morphology of angiogenesis in human cancer: a conceptual overview, histoprognostic perspective and significance of neoangiogenesis

This paper reviews the histomorphological aspects of angiogenesis and neoangiogenesis, quantitative and qualitative, and their applications in prognostic evaluation of neoplastic diseases. The merits and weak points of intratumoral microvessel density (MVD), a widely regarded bona fide predictor of tumour growth, metastases and patient survival, are discussed. Total microvascular area (TVA) has been found useful in recent prognostic studies utilizing newer immunohistochemical vascular markers. Of particular significance is the fact that MVD and TVA are most predictive of patient outcome in those tumours that induce significant neoangiogenesis, namely carcinomas of breast and prostate, and haematological malignancies. In contrast, carcinomas of lung and urinary bladder do not show significant associations of MVD and TVA with poor prognosis, reflecting differences in angiogenic mechanisms. In gliomas, MVD appears to correlate with outcome in high-grade, but not low-grade tumours, and does not correlate with tumour cellularity in the infiltrating portions of the tumour, reflecting a paucity of neoangiogenesis and directional vascular growth. Recent studies have found CD105, Tie-2/Tek and vascular endothelial growth factor receptors to be the best markers of neoangiogenesis. The vascular parameters so measured correlate better with overall and disease-free survival in breast, colon and lung carcinoma than panendothelial markers such as CD31. A correlation of vascular patterns with prognosis has been established in ocular melanomas, glioblastomas and squamous carcinomas of head and neck region. Vascular networks with closed loops are closely associated with mortality due to metastases in uveal melanomas. Fewer bizarre glomeruloid vessels and prominent classical capillary pattern was an independent predictor of longer survival in glioblastoma. Therefore a judicious combination of quantitative and qualitative microscopic angiogenic parameters, with emphasis on neoangiogenesis and vascular patterns wherever applicable, should be an integral component of a more consistent tumour staging system for accurate prognostic evaluation of tumours, selection of optimal anti-angiogenic therapy and pertinent research.

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.

Gene expression of angiogenic factors correlates with metastatic potential of prostate cancer cells

We hypothesize that expression of proangiogenic genes correlates with the metastatic potential of prostate cancer cells. LNCaP, DU-145, and PC-3 are prostate cancer cell lines with low, moderate, and high metastatic potential, respectively, as we demonstrated by their capacity to invade an extracellular matrix, an established tumor invasion assay. The constitutive gene expression of the proangiogenic factors, vascular endothelial growth factor, intercellular adhesion molecule-1, interleukin-8, and transforming growth factor-beta2, was significantly greater in the more metastatic DU-145 and PC-3 cells as compared with LNCaP cells. Matrix metalloproteinase (MMP)-9 is thought to contribute to the invasive phenotype of tumor cells. PC-3 cells showed increased expression of MMP-9 and membrane type 4-MMP as compared with LNCaP and DU-145. Tissue inhibitors of metalloproteinase 1 and 4 gene expression were elevated in DU-145 and PC-3 cells, but paradoxically, LNCaP cells had undetectable levels of these genes. We transfected and overexpressed MMP-9 in poorly metastatic LNCaP cells and measured their invasive activity. Transient expression of human MMP-9 in LNCaP cells produced a 3-5-fold increase in MMP-9 activity with a comparable increase in invasiveness. Antisense ablation of the expression of MMP-9 in DU-145 and PC-3 cells produced concomitant inhibition of the gene expression of the proangiogenic factors, vascular endothelial growth factor, and intercellular adhesion molecule-1 (ICAM-1). Treatment of DU-145 and PC-3 cells with a selective chemical inhibitor of MMP-9 proteinase activity also inhibited their invasive activity. These results support our hypothesis that metastatic potential of prostate cancer cells correlates with expression of proangiogenic factors.

Randomized phase II trial of docetaxel plus thalidomide in androgen-independent prostate cancer

PURPOSE

Both docetaxel and thalidomide have demonstrated activity in androgen-independent prostate cancer (AIPC). We compared the efficacy of docetaxel to docetaxel plus thalidomide in patients with AIPC.

METHODS

Seventy-five patients with chemotherapy-naïve metastatic AIPC were randomly assigned to receive either docetaxel 30 mg/m(2) intravenously every week for 3 consecutive weeks, followed by a 1-week rest period (n = 25); or docetaxel at the same dose and schedule, plus thalidomide 200 mg orally each day (n = 50). Prostate-specific antigen (PSA) consensus criteria and radiographic scans were used to determine the proportion of patients with a PSA decline, and time to progression.

RESULTS

After a median potential follow-up time of 26.4 months, the proportion of patients with a greater than 50% decline in PSA was higher in the docetaxel/thalidomide group (53% in the combined group, 37% in docetaxel-alone arm). The median progression-free survival in the docetaxel group was 3.7 months and 5.9 months in the combined group (P =.32). At 18 months, overall survival in the docetaxel group was 42.9% and 68.2% in the combined group. Toxicities in both groups were manageable after administration of prophylactic low-molecular-weight heparin in the combination group.

CONCLUSION

In this randomized phase II trial, the addition of thalidomide to docetaxel resulted in an encouraging PSA decline rate and overall median survival rate in patients with metastatic AIPC. After the prophylactic low-molecular-weight heparin was instituted to prevent venous thromboses, the combination regimen was well tolerated. Larger randomized trials are warranted to assess the impact of this combination.

Decreased Pigment Epithelium-Derived Factor Is Associated with Metastatic Phenotype in Human and Rat Prostate Tumors

Pigment epithelium-derived factor, a potent angiogenesis inhibitor in the eye, is also expressed in the prostate. Prostate size and angiogenesis is increased in pigment epithelium-derived factor knockout mice, and pigment epithelium-derived factor is down-regulated in some prostate cancers. To investigate whether pigment epithelium-derived factor expression correlates with tumor progression, we examined 5 Dunning rat prostate sublines with different growth rates, differentiation, androgen dependence, vascular density, and metastatic ability and 26 human prostate cancers of Gleason score 8-10 obtained from patients at transurethral resection selected to represent two groups, with and without metastases at diagnosis. By Western blot, real-time quantitative reverse transcription-PCR, and immunostaining, pigment epithelium-derived factor was detected in highly differentiated, nonmetastatic, androgen-sensitive Dunning tumors and in the anaplastic, androgen insensitive but nonmetastatic Dunning tumors. In contrast, the metastatic Dunning tumor sublines showed very low pigment epithelium-derived factor expression levels. In human cancer tissues, by immunohistochemistry and real-time quantitative reverse transcription-PCR, patients without metastases at diagnosis had higher tumor pigment epithelium-derived factor levels than tumors from patients with metastases at diagnosis. In both the rat model and in the human tumors, the proliferation index and vascular count, as determined by Ki-67 staining and endoglin and/or factor VIII-related antigen staining, inversely correlated with pigment epithelium-derived factor mRNA levels. These observations indicate that loss of pigment epithelium-derived factor expression could be associated with the progression toward a metastatic phenotype in prostate cancer.

Phase II trial and pharmacokinetic study of thalidomide in patients with metastatic colorectal cancer

INTRODUCTION

This study was designed to estimate the percentage of objective tumor responses, toxicity profile, and obtain additional information about the plasma pharmacokinetics of thalidomide in patients with refractory and progressing metastatic colorectal cancer.

STUDY DESIGN

This phase II clinical trial was conducted according to the two-stage Simon method with the inclusion of consecutive patients. The study protocol was approved by the Institutional Review Board (IRB) of the Academic Hospital (HCPA) of the Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.

PATIENTS AND METHODS

Seventeen patients with previously treated, refractory progressive metastatic colorectal cancer were eligible. Six patients had prior radiotherapy. The patients had a median of one previous chemotherapy regimen. Patients were initially treated with 200 mg/day of thalidomide with an increase in dose by 200 mg/day every 2 weeks until a final daily dose of 800 mg/day was achieved. Patients were evaluated every 8 weeks for response by radiographic criteria. Plasma pharmacokinetics studies were performed in four patients at 200 mg level and in one patient at 600 mg during the first 24 h.

MAIN OUTCOME MEASURES AND RESULTS

A total of 17 patients were accrued, all of them being evaluable for toxicity and 14 for response. Thalidomide was well tolerated, with constipation, somnolence, dizziness, and dry mouth being the major toxicities. There were no objective response or stable disease. The median survival was 3.6 months. Single-agent thalidomide is a generally well-tolerated drug that showed no antitumor activity in patients with advanced pretreated metastatic colorectal cancer. Although thalidomide did not show antitumor activity in this patient population, future studies of this agent in patients at initial stages of the disease (when its antiangiogenic properties may be more relevant to disease progression) could be considered.

Human prostate cancer risk factors

Prostate cancer has the highest prevalence of any nonskin cancer in the human body, with similar likelihood of neoplastic foci found within the prostates of men around the world regardless of diet, occupation, lifestyle, or other factors. Essentially all men with circulating androgens will develop microscopic prostate cancer if they live long enough. This review is a contemporary and comprehensive, literature-based analysis of the putative risk factors for human prostate cancer, and the results were presented at a multidisciplinary consensus conference held in Crystal City, Virginia, in the fall of 2002. The objectives were to evaluate known environmental factors and mechanisms of prostatic carcinogenesis and to identify existing data gaps and future research needs. The review is divided into four sections, including 1) epidemiology (endogenous factors [family history, hormones, race, aging and oxidative stress] and exogenous factors [diet, environmental agents, occupation and other factors, including lifestyle factors]); 2) animal and cell culture models for prediction of human risk (rodent models, transgenic models, mouse reconstitution models, severe combined immunodeficiency syndrome mouse models, canine models, xenograft models, and cell culture models); 3) biomarkers in prostate cancer, most of which have been tested only as predictive factors for patient outcome after treatment rather than as risk factors; and 4) genotoxic and nongenotoxic mechanisms of carcinogenesis. The authors conclude that most of the data regarding risk relies, of necessity, on epidemiologic studies, but animal and cell culture models offer promise in confirming some important findings. The current understanding of biomarkers of disease and risk factors is limited. An understanding of the risk factors for prostate cancer has practical importance for public health research and policy, genetic and nutritional education and chemoprevention, and prevention strategies.

The Combination of Antiangiogenic and Cytotoxic Agents in the Treatment of Prostate Cancer

Metastatic prostate cancer is one of the leading causes of cancer death in men. Although initially responsive to hormone therapy, it eventually progresses in almost all patients. For this reason, there has been a search for novel agents to use in the fight against androgen-independent prostate cancer. Antiangiogenesis is a relatively new antitumor strategy that has been employed in the treatments of many malignancies. As prostate cancer is likely dependent on angiogenesis for its growth and progression, it would logically serve as a good target for this modality. Initially met with great enthusiasm, antiangiogenic drugs have seen only limited success when used as single agents. This has been attributed to many possible etiologies including lack of cytotoxicity and use in situations of large tumor burden. In order to overcome these problems, many investigators are combining antiangiogenic agents with more traditional cytotoxic chemotherapy regimens in hope of augmenting the effects of either drug alone. This article will review the background of angiogenesis inhibition and the use of such combinations in metastatic prostate cancer.

Significance of microvascular density (MVD) in cervical cancer recurrence

The purpose of this retrospective study of 118 patients with squamous cell cervical cancer from January 1990 to December 1993 was to evaluate angiogenesis as predictive factor of recurrence in cervical cancer stages II-III treated with standard radiotherapy. Microvessel density (MVD) was evaluated and correlated with other prognostic factors. MVD was greater than 20 in 67.8% of patients with recurrence (P = 0.002) in comparison to 39% of patients without. Disease-free survival was shorter in stage IIA and MVD >20 (P = 0.0193) as well as for stage IIB (P < 0.05 ), but not for IIIB (P = 0.1613 ). Global survival was significantly shorter when MVD was >20 (P = 0.0316). For stage IIA and MVD >20 survival was shorter (P = 0.0008) for stage IIB (P < 0.05) but not for IIIB (P = 0.14). Patients younger than 40 years and MVD >20 had poorer disease-free interval and survival (P = 0.0029). MVD in patients with squamous cell cervical cancer stage II and age younger than 40 may play a role in predicting recurrence and survival.

Current status of thalidomide and its role in the treatment of metastatic prostate cancer

Following the discovery of its anti-angiogenic properties and despite its tragic history, thalidomide has re-surfaced in the field of oncology. Concurrent with its evaluation in various clinical trials for cancer, thalidomide's mechanism of action is sought and new analogues with improved efficacy and pharmacological profile are emerging. This review is a critical evaluation of thalidomide metabolism, molecular targets, anti-angiogenic activity and clinical efficacy with an emphasis on metastatic prostate cancer.

The long-term effect of recombinant tissue-plasminogen-activator (rt-PA) on edema formation in a large-animal model of intracerebral hemorrhage

Hematoma puncture, fibrinolysis, and aspiration of the liquefied clot is a promising new treatment strategy for large intracerebral hemorrhages (ICH). Characteristics of the cellular injury and neuronal and glial cell death associated with ICH and the administration of fibrinolytic agents still need to be defined. We developed a porcine model to study the histopathological effects of recombinant tissue-Plasminogen-Activator (rt-PA) on perihematomatous cell integrity. In 20 pigs, lobar hematomas were induced by intracranial pressure (ICP)-controlled injections of 7.6 +/- 1.6 ml of autologous blood into the white matter of the right frontal hemisphere. In nine animals, the clots were lysed with rt-PA, thereby facilitating aspiration 2 h after hematoma induction. In 11 control pigs, the hematoma resorption followed its natural course. The rate of hematoma reduction and edema formation over 10 days was evaluated on planimetry of the MRI data and correlated to the histopathological changes found at autopsy. Although rt-PA significantly accelerated clot resolution compared to controls (p < 0.02), the increase of perihematomatous edema volume within 10 days was not significantly ameliorated in rt-PA-treated animals compared to controls on MRI. The extent of inflammatory infiltrates on histology was more pronounced in animals treated with rt-PA. In conclusion, despite significant reduction in the size of the hematoma clot liquefication with rt-PA and aspiration invokes a substantial inflammatory response when studied after 10 days and does not result in a reduction of the perihematomatous edema.

Associations of serum testosterone with microvessel density, androgen receptor density and androgen receptor gene polymorphism in prostate cancer

PURPOSE

We investigate potential associations of serum testosterone with microvessel density, androgen receptor expression and AR gene polymorphism in men with untreated prostate cancer.

MATERIAL AND METHODS

Serum luteinizing hormone, follicle-stimulating hormone, estradiol and testosterone were determined in men with newly diagnosed prostate cancer. The number of tumor vessels per 0.46 mm. and androgen receptor density (as the percent positive nuclei) were quantified immunohistochemically on prostate cancer areas of prostate biopsy specimens. Polymorphisms within the AR gene (number of CAG repeats) were determined by polymerase chain reaction and restriction fragment length polymorphism analysis using DNA from peripheral blood.

RESULTS

The 39 men entered into this study were grouped into 16 with low (3 ng./ml. or less, group 1) and 23 with normal (greater than 3 ng./ml., group 2) serum testosterone. Mean prostate specific antigen +/- SD was significantly lower in group 1 than in group 2 (18.8 +/- 11.1 versus 27.2 +/- 12.2 ng./ml., p = 0.03). Mean Gleason score (7.4 +/- 1.3 versus 6.0 +/- 1.2, p = 0.01), androgen receptor density (96.6% +/- 2.8% versus 84.8% +/- 7.2%, p = 0.03) and tumor vessel density (63.0 +/- 30.8/0.46 versus 39.0 +/- 22.9/0.46 mm.2, p = 0.007) were significantly higher in group 1 than in group 2. The number of CAG repeats within the AR gene did not correlation with serum androgen.

CONCLUSIONS

Low serum testosterone in men with newly diagnosed prostate cancer is associated with higher tumor microvessel and androgen receptor density as well as with higher Gleason score, suggesting enhanced malignant potential.

Angiogenin and gestational trophoblastic tumors, a promising prognostic marker

The aim of this study was to evaluate the diagnostic and prognostic values of serum angiogenin concentration in cases with gestational trophoblastic diseases (GTDs). Seventy-two patients with GTDs and 20 first trimester healthy pregnant women (controls) participated in this study. According to the WHO scoring system, GTDs were subgrouped into 24 hydatiform mole spontaneous regression (HMSR), 18 postmolar gestational trophoblastic tumors of high risk (PMHR), 16 low-risk choriocarcinoma, and 14 high-risk choriocarcinoma. Before treatment, a blood sample from each case was assayed for human chorionic gonadotrophin , subunit (hCGb) by radioimmunoassay and angiogenin by enzyme immunoassay. Follow-up hCGb and angiogenin assays were carried out for 1 year after treatment. Pretreatment of abnormal values of serum angiogenin (> 711 ng/ml, upper 95% confidence interval of controls) was encountered in 100% of PMHR cases compared to no single case of HMSR. Serum angiogenin levels in low- and high-risk cases with choriocarcinoma were significantly higher than in controls. Abnormal high values were encountered in 25% and 86% of cases, respectively. None of the low-risk cases exceeded 920 ng/ml, while 72% of high-risk cases exceeded this value. Serial angiogenin assays were correlated with disease progression and were positively correlated with serum hCGb (r = 0.75, p < 0.01). In conclusion, serum angiogenin may be a valuable marker of differential diagnosis of GTDs and its serial measurements are suggestive of remission and effective therapeutic intervention or disease progression.

Effects of various steroids on platelet-derived endothelial cell growth factor (PD-ECGF) and its mRNA expression in uterine endometrial cancer cells

Progestins diminish the estrogen-induced angiogenic potential related to basic fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF) in uterine endometrial cancer cells. This led us to study the effect of various steroids on the expression of platelet-derived endothelial cell growth factor (PD-ECGF) as the other pertinent angiogenic factor in well-differentiated uterine endometrial cancer cell line Ishikawa. In Ishikawa cells, estradiol induced the expression of PD-ECGF and its mRNA. The estrogen-induced expression was increased approximately two-fold by progesterone and by its metabolite, 17alpha-hydroxyprogesterone, but not by medroxyprogesterone acetate (MPA). Therefore, progesterone and 17alpha-hydroxyprogesterone as endogenous steroids might induce PD-ECGF-related angiogenic potential in uterine endometrial cancer cells, but not MPA as a synthetic steroid. In conclusion, the failure of PD-ECGF induction by MPA might be the great merit of anti-angiogenic treatment with MPA for uterine endometrial cancers.

Hypoxia induces proteasome-dependent degradation of estrogen receptor alpha in ZR-75 breast cancer cells

Regulation of estrogen receptor alpha (ERalpha) plays an important role in hormone responsiveness and growth of ER-positive breast cancer cells and tumors. ZR-75 breast cancer cells were grown under conditions of normoxia (21% O(2)) or hypoxia (1% O(2) or cobaltous chloride), and hypoxia significantly increased hypoxia-inducible factor 1alpha protein within 3 h after treatment, whereas ERalpha protein levels were dramatically decreased within 6-12 h, and this response was blocked by the proteasome inhibitor MG-132. In contrast, hypoxia induced only minimal decreases in cellular Sp1 protein and did not affect ERalpha mRNA; however, hypoxic conditions decreased basal and 17beta-estradiol-induced pS2 gene expression (mRNA levels) and estrogen response element-dependent reporter gene activity in ZR-75 cells. Although 17beta-estradiol and hypoxia induce proteasome-dependent degradation of ERalpha, their effects on transactivation are different, and this may have implications for clinical treatment of mammary tumors.

Vascular endothelial growth factor (VEGF) is expressed by neoplastic Hodgkin-Reed-Sternberg cells in Hodgkin's disease

Vascular endothelial growth factor (VEGF) is involved in tumour angiogenesis, an important process for the growth and metastatic potential of solid tumours. Numerous studies have demonstrated up-regulation of VEGF at both mRNA and protein level in various tumours and a correlation with advanced stage and prognosis has been demonstrated in some cases. Limited information exists about its role in lymphoid malignancies and in particular, Hodgkin's disease. The present study examined the immunohistochemical expression of VEGF using the monoclonal antibody VG1 in a series of 61 cases of Hodgkin's disease, including both classical Hodgkin's disease and the nodular lymphocyte predominance variant, and correlated these results with microvessel density, using an anti-CD31 monoclonal antibody. In 41 cases (70.6%) of classical Hodgkin's disease and one of the three cases of nodular lymphocyte predominance Hodgkin's disease, the neoplastic Reed-Sternberg and Hodgkin cells expressed VEGF. The staining observed was cytoplasmic, either diffuse or with a focal paranuclear distribution. Macrophages were always positive, while reactive lymphocytes showed occasional positivity. A variable amount of strong extracellular staining was also observed in the tissue stroma and intravascular plasma staining was prominent. There was no statistically significant relationship between VEGF expression and the subtype of Hodgkin's disease or microvessel density. In vitro studies using the Reed-Sternberg cell lines L428 and KM-H2 were also performed in both normoxia and hypoxia and VEGF protein production was assessed by flow cytometry (FACS), immunoassay of cell culture supernatant, and RT-PCR. Analysis by FACS demonstrated a subset of cells in both cell lines reacting with VG1 and analysis of secreted VEGF (pg/ml per 1x10(6) cells) in cell culture supernatant confirmed the normoxic production in both cell lines and significant hypoxic induction (p<0.005). Additionally, both cell lines expressed VEGF mRNA, as demonstrated using the RT-PCR method. In conclusion, neoplastic cells express VEGF in Hodgkin's disease, as is the case in solid tumours, and this expression may be induced by hypoxia. The presence of VEGF in reactive macrophages and in the extracellular matrix might facilitate tumour progression.

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.

Prognostic significance of microvessel density, vascular cuffing and vascular endothelial growth factor expression in ovarian carcinoma: a special review for clear cell adenocarcinoma

Our purpose is to demonstrate the relationship between microvessel density (MVD), vascular cuffing (VC), vascular endothelial growth factor (VEGF) expression and clinicopathological parameters in ovarian cancer. Surgical specimens from 105 primary ovarian cancers were examined for vascularization and VEGF expression by immunohistochemical staining. The higher MVD group (MVD> or =70) and the positive VEGF group were associated with better progression-free survival only in early stages. The significant association of the MVD with better progression-free survival was recognized only in the patients with clear cell adenocarcinomas. The complete VC group showed a similar trend as MVD though there was no statistical difference. A multivariate analysis revealed MVD to correlate independently with progression-free survival. In ovarian carcinoma, MVD was found to be an independent prognostic factor. In addition, the higher MVD with clear cell adenocarcinoma had the better prognosis. The clinicopathological role of angiogenesis should be analyzed taking account of histologic type.

Evidence for telomerase involvement in the angiogenesis of astrocytic tumors: expression of human telomerase reverse transcriptase messenger RNA by vascular endothelial cells

OBJECT

Evidence from recent in vitro studies indicates that reactivation of telomerase, the enzyme that synthesizes the telomere ends of chromosomes, is a crucial event in the unlimited clonal expansion of endothelial cells that precedes the neoplastic conversion of these cells. It is known that high-grade gliomas express telomerase and that, in these neoplasms, proliferating endothelial cells may undergo transformational changes with development of sarcomatous components within the primitive tumor. To assess whether telomerase is involved in the endothelial cell proliferation that characterizes brain tumor angiogenesis, the authors investigated at the single-cell level the expression of messenger (m)RNA for the human telomerase catalytic subunit human telomerase reverse transcriptase (hTERT) by vascular cells of astrocytic tumors.

METHODS

The in situ hybridization (ISH) method was performed by processing histological sections with specific riboprobes for hTERT and for c-myc, an oncogene that is known to upregulate hTERT. Results of the ISH studies were compared with proliferative activity, as estimated by Ki-67 immunostaining. The expression of hTERT mRNA by vascular endothelial cells was related to the histological grade of the tumor because it was detected in five (29%) of 17 low-grade astrocytomas, nine (56%) of 16 anaplastic astrocytomas, and 19 (100%) of 19 glioblastomas multiforme (GBMs). Expression of c-myc mRNA was strictly correlated with that of hTERT mRNA. In low-grade astrocytomas and anaplastic astrocytomas, a dissociation was noted between hTERT mRNA expression and the proliferation rate of endothelial cells. Conversely, GBMs displayed a significant correlation between the level of hTERT mRNA expression and endothelial cell proliferation. Data from an in vitro assay in which human umbilical vein endothelial cells were stimulated to proliferate by adding vascular endothelial growth factor and an ISH study of newly formed vessels surrounding brain infarcts confirmed that expression of hTERT mRNA does not merely reflect the proliferative status of endothelial cells but represents a specific feature of brain tumor neovascularization.

CONCLUSIONS

The results of this study are consistent with a role of telomerase in the angiogenesis of astrocytic tumors. Expression of hTERT mRNA by tumor vascular cells is an early event during the progression of astrocytic tumors, which precedes endothelial cell proliferation and may represent a first sign of dedifferentiation. Other than elucidating the mechanisms of tumor angiogenesis, these results encourage research on antitelomerase drugs for the treatment of malignant gliomas.

Neoangiogenesis in squamous cell carcinoma of the larynx - biological and prognostic associations

Tumor angiogenesis has been related to tumor growth and an increased probability of metastatic spread. Previous studies have led to conflicting views regarding the prognostic significance of angiogenesis in squamous cell carcinoma of the head and neck. To evaluate the role of tumor angiogenesis in the biology of squamous cell carcinoma of the larynx, we quantified the microvascular network in 59 primary laryngeal carcinomas and looked for an association with outcome. Microvessels were stained immunohistochemically using antibodies for factor VIII-related antigen and the antibody JC70 (CD-31). In each case, microvessels were counted in three fields at x200 magnification, in areas of most intense neovascularization. We found a significantly higher number of microvessels in tumors showing deeper levels of invasion.

Vascular differences detected by MRI for metastatic versus nonmetastatic breast and prostate cancer xenografts

Several studies have linked vascular density, identified in histologic sections, to "metastatic risk." Functional information of the vasculature, not readily available from histologic sections, can be obtained with contrast-enhanced MRI to exploit for therapy or metastasis prevention. Our aims were to determine if human breast and prostate cancer xenografts preselected for differences in invasive and metastatic characteristics established correspondingly different vascular volume and permeability, quantified here with noninvasive MRI of the intravascular contrast agent albumin-GdDTPA. Tumor vascular volume and permeability of human breast and prostate cancer xenografts were characterized using MRI. Parallel studies confirmed the invasive behavior of these cell lines. Vascular endothelial growth factor (VEGF) expression in the cell lines was measured using ELISA and Western blots. Metastasis to the lungs was evaluated with spontaneous as well as experimental assay. Metastatic tumors formed vasculature with significantly higher permeability or vascular volume (P<.05, two-sided unpaired t test). The permeability profile matched VEGF expression. Within tumors, regions of high vascular volume usually exhibited low permeability whereas regions of low vascular volume exhibited high permeability. We observed that although invasion was necessary, without adequate vascularization it was not sufficient for metastasis to occur.

Matrix metalloproteinases: pro- and anti-angiogenic activities

Matrix metalloproteinases (MMP) are a family of structurally related proteinases most widely recognized for their ability to degrade extracellular matrix, although recent investigations have demonstrated other biologic functions for these enzymes. MMP are typically not constitutively expressed, but are regulated by: (1) cytokines, growth factors, and cell-cell and cell-matrix interactions that control gene expression; (2) activation of their proenzyme form; and (3) the presence of MMP inhibitors [tissue inhibitors of metalloproteinases, (TIMP)]. MMP have important roles in normal processes including development, wound healing, mammary gland, and uterine involution, but are also involved in angiogenesis, tumor growth, and metastasis. Angiogenesis, characteristically defined as the establishment of new vessels from pre-existing vasculature, is required for biologic processes such as wound healing and pathologic processes such as arthritis, tumor growth, and metastasis. Blocking of MMP activity has been studied for potential therapeutic efficacy in controlling such pathologic processes. Synthetic MMP inhibitors, most notably the hydroxymates, have been engineered for this purpose and are presently in clinical trial. These inhibitors may have broad versus specific MMP inhibitory activity. As increased non-matrix degrading capabilities of MMP are recognized, however, i.e., cytokine activation, processing of proteins to molecules of distinct biologic function, it becomes less clear whether the nonselective inhibition of MMP activity for all pathologic processes involving MMP is appropriate. This review focuses upon the contribution of MMP to the process of tumor invasion and angiogenesis, and discusses the design and use of MMP inhibitors as therapeutic agents in these processes.

Vascular density (tumor angiogenesis) in non-Hodgkin's lymphomas and florid follicular hyperplasia: a morphometric study

Tumor angiogenesis is required for tumor growth and metastasis. A statistically significant correlation has been demonstrated between prognosis and the microvessel density (a measure of tumor angiogenesis) of solid tumors, particularly of the breast and prostate, and lymphoid neoplasms. The aim of this study was to establish whether a correlation exists between vascular density and the malignant category of Non-Hodgkin's Lymphoma (NHL) defined by two classification systems (Kiel and Working Formulation). We also tested whether florid follicular hyperplasia (FFH) and follicular lymphomas (FL) behave as new vessel stimulating conditions. Eighty-nine NHL lymph node biopsies were reviewed and categorized according to the Kiel Classification and Working Formulation. Twelve FL were also selected and compared to 12 FFH biopsies. Vessels were highlighted by immunostaining with anti-Factor VIII antibody and quantified both by counting higher vascular density fields and by estimating the proportional vascular area. The results showed a statistically significant difference between low and high grade NHL, when classified in either the Working Formulation (p=0.0015) or the Kiel Classification (p=0.002). No differences were found in vessel counts between Working formulation intermediate and high grade lymphomas. Vascular density is similar when FFH and FL interfollicular areas are compared.