Microvessel quantification in primary colorectal carcinoma: an immunohistochemical study

Selenium-Enriched Saccharomyces cerevisiae Reduces the Progression of Colorectal Cancer

Colorectal cancer is one of the most common causes of mortality in the world while malnutrition is responsible for one third of the problem. Selenium has been recommended for prevention of colorectal cancer. The present study was conducted to investigate the effect of selenium-enriched Saccharomyces cerevisiae in reducing colorectal cancer progression in rats. Five groups of 170-200-g weight rats (n = 40) including healthy and cancer controls, Saccharomyces cerevisiae, selenium, and selenium-enriched Saccharomyces cerevisiae-treated groups were examined. All animals except healthy control group received 40 mg 1,2-dimethylhydrazine (DMH) per kilogram weight of rat twice a week. The healthy group received normal saline, and synchronously, selenium group received soluble selenium (4 mg/mL), Saccharomyces cerevisiae and selenium-enriched groups received yeast with the density of 5 × 10⁸ CFU/mL by daily gavage. All treatments were carried out for 5 weeks after the last injection. Animals were autopsied, and aberrant crypt foci (ACF) of ejected colon were studied in the 40th week. Microscopic sections were prepared for hematoxylin and eosin. Furthermore, immunohistochemical staining of CD31, BCL2, and P53 antibodies was performed. Macroscopic and microscopic evaluations showed that DMH had the least destructive effect in selenium-enriched Saccharomyces cerevisiae group compared to other groups. Selenium-enriched Saccharomyces cerevisiae reduces colorectal cancer progression by various mechanisms such as reduction in the number and size of ACF and alteration in the function of the proteins such as P53, BCL2, and CD31.

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.

New insights into the lymphovascular microanatomy of the colon and the risk of metastases in pT1 colorectal cancer obtained with quantitative methods and three-dimensional digital reconstruction

AIMS

UK faecal occult blood test screening has tripled the proportion of pT1 colorectal cancers. The risk of metastasis is predicted by depth of invasion, suggesting that access to deep lymphovascular vessels is important. The aim of this study was to quantify the distribution and size of the submucosal vasculature, and generate a novel three-dimensional (3D) model to validate the findings.

METHODS AND RESULTS

Thirty samples of normal large bowel wall were immunostained with CD31, a vascular endothelium marker, to identify blood vessels, which were quantified and digitally analysed for their number, circumference, area and diameter in the deep mucosa and submucosa (Sm1, Sm2, and Sm3). The model required serial sections, a double immunostain (using CD31 and D2-40), and 3D reconstruction. Significant differences were shown between submucosal layers in the number, circumference and area of vessels (P < 0.001). Blood vessels were most numerous in the mucosa (11.79 vessels/0.2 mm(2)) but smaller [median area of 247 μm(2) , interquartile range (IQR) 162-373 μm(2)] than in Sm2, where they were fewer in number (6.92 vessels/0.2 mm(2)) but considerably larger (2086 μm(2), IQR 1007-4784 μm(2)). The 3D model generated novel observations on lymphovascular structures.

CONCLUSIONS

The number and size of blood vessels do not increase with depth of submucosa, as hypothesized. The distribution of vessels suggests that we should investigate the area or volume of submucosal invasion rather than the depth.

Increased angiogenesis and FGFR protein expression indicate a favourable prognosis in bladder cancer

Compared to other members of the fibroblast growth factor receptor (FGFR) family, only few studies investigate FGFR3 in tumour angiogenesis. We investigated the connection between angiogenesis and FGF/FGFR expression including FGFR3 mutation status in urothelial carcinomas. Immunohistochemistry was performed in invasive and non-invasive urothelial cancers of 61 patients. Protein expression of CD31, factor VIII (FVIII), FGF-1/2, FGFR1, FGFR3 and FGFR4 and FGFR3 mutation status were evaluated. Morphometric assessment of angiogenesis including microvessel count (MVC) and vascular surface area (VSA) was analysed. Correlation and survival analyses (overall survival (OS) and disease-free survival (DFS)) with univariate and multivariate analyses were performed. CD31 values (MVC and VSA) significantly correlated with OS and DFS. OS and DFS were significantly better in patients with FGFR3 overexpression. Multivariate analysis revealed FGFR3 protein expression and tumour grading (WHO classification 2004) as independent prognostic factors of OS and VSA of CD31 and FGFR3 protein expression of DFS. FGFR3 mutation status was correlated with VSA measured by FVIII. FGFR3 may be able to induce a pro-angiogenic phenotype in urothelial carcinomas and significantly influence prognosis. Consequently, FGFR3 is a potential therapeutic target also from the angiogenesis perspective.

The clinical implication of cancer-associated microvasculature and fibroblast in advanced colorectal cancer patients with synchronous or metachronous metastases

BACKGROUND

We aimed to evaluate the clinical significance of microvessel density (MVD), lymphatic vessel density (LVD), and cancer-associated fibroblasts (CAFs) in relation to tumor location in advanced colorectal cancer (CRC).

METHODS

Using immunohistochemistry, we examined 181 advanced CRC patients for CD31 and D2-40 to measure MVD and LVD, respectively, α-smooth muscle actin (SMA) and desmin to identify CAFs, and PTEN to examine genetic changes of CAFs. To evaluate the regional heterogeneity of these properties, we examined tissue from four sites (the center and periphery of the primary cancer, a distant metastasis, and a lymph node metastasis) in each patient.

RESULTS

MVD, LVD, and CAFs showed significant heterogeneity with respect to the tumor location. LVD was the greatest in the center of the primary cancers and the amount of CAFs was the lowest in distant metastases. In distant metastases, those from the lung had higher LVD and MVD, but fewer CAFs than those from the liver, peritoneum, or ovary. Patients with low MVD and LVD in the center of the primary cancer had worse outcomes and patients with few CAFs in distant metastases and in the primary tumor had a lower survival rate. PTEN expression in CAFs in distant metastases was lost in 11 of 181 CRC patients (6.1%), which was associated with a worse prognosis.

CONCLUSIONS

The microenvironment, including cancer-associated microvasculature and fibroblasts, is heterogeneous with respect to the tumor location in CRC patients. Therefore, heterogeneity of microenvironments should be taken into account when managing CRC patients.

Microvascular morphometrics of the hypophysis and pituitary tumors: from bench to operating theatre

The idea that microvasculature might be a histopathological biomarker in the prognosis and treatment of tumors is garnering even more attention in the scientific community. The roles of neovascularity in tumor progression and metastasis, have become a hot-topic of investigation in cancer research. A number of methods of quantitatively analyzing pituitary adenoma microvasculature have been applied, and fractal analysis is emerging as a potential effective model for this aim. Additionally, new and more specific immunological techniques have been developed for the detection of microvessels. CD105 (Endoglin) has been proposed as a valuable antigen that marks only newly formed vessels, rather than the entire tumor microvascular system. The combination of different types of immunostaining techniques for the detection of microvessels in pituitary adenomas with fractal analysis as an objective and computer-aided technique to quantify and describe morphological aspects of microvessels has potential implications in future clinical and surgical applications. Tumor treatments, such as anti-angiogenic therapy, as well as intraoperative tools, stand to be enhanced by increasing advances in microvascular research. We here review the methods used for the quantitative analysis of microvessels of the pituitary in its physiopathological states, with the aim to show the pituitary adenoma as a model for the study of neoplastic angioarchitecture and the importance of the introduction of new techniques for the study of angiogenesis, with the relative scientific, medical and surgical implications.

Prognostic significance of mast cell number and microvascular density for the survival of patients with primary colorectal cancer

BACKGROUND AND AIM

The prognostic relevance of tumor-related angiogenesis and mast cell presence in colorectal cancer remains controversial. The aim of the current study was to assess the mast cell and microvessel densities (MCD and MVD) in the invasive front of colorectal cancers and to determine their prognostic relevance for survival of the patient with colorectal carcinoma.

METHODS

Histochemistry and immunohistochemistry were used to identify mast cells by toluidine blue (TB) histochemical staining and tryptase (Try) immunohistochemical staining and to determine the MVD in 106 biopsies from patients with 57 colonic and 49 rectal primary cancers. The MVD was assessed using CD31 as an endothelial cell marker.

RESULTS

Significant positive correlations were found between the MVD in the 'hot spots' and MCD-Try and MCD-TB (R = 0.623 and R = 0.414, respectively, P < 0.001). The survival analyses showed that the patients with hypovascular tumor tissues had significantly longer survival than those with hypervascular tumor biopsies (P < 0.0001). Analogous significant correlation was observed for MCD-Try: patients with low MCD-Try had significantly better prognosis compared to those with high MCD (P = 0.038). In the multivariate Cox's hazard analysis of the 'hot spots' MVD was found to be an independent prognostic factor (P = 0.0007), together with the presence of invasion of lymph vessels (P = 0.017) and the presence of regional lymph node metastases (P = 0.028).

CONCLUSION

We suggest that the assessment of MVD and tryptase-positive mast cells in the invasive front of the primary colorectal cancer could be a useful tool for prognosis of patients after surgical therapy.

[Prognostic role of vascularisation and proliferation in rectal cancer with liver metastasis]

BACKGROUND

The present study was designed to provide an analysis of factors for angiogenesis and proliferation.

MATERIAL AND METHOD

We analyzed tumor tissues from 37 rectal cancer patients with concurrent or subsequent liver metastasis underwent preoperative radiotherapy, surgery and adjuvant chemotherapy. Immunohistochemistry was used for expression of proliferation (staining with anti-Ki67: MIB-1) and for detection of microvessel density (MVD, expressed by CD34). Clinicopathological findings were compared with outcome with emphasis to IHC.

RESULTS

A vascular enumeration and pN status and the time of presence of the metastases has shown prognostic role along with the factors above. Increased proliferative activity of the tumor as expressed by MIB-1 staining has no prognostic value, similarly to the localization of tumor, gender, age or grading.

SUMMARY

Different prognostic and predictive factors in colorectal cancer have been reported. Higher pN status and tumor vascularisation has been linked to poor prognosis in overall survival and tumor recurrence.

[Assessment of angiogenesis expression and its relationship with prognosis of colorectal cancer by conventional and computer-assisted histopathological image analysis]

PURPOSE

To quantify the degree of angiogenesis by conventional method (microvessel density, MVD) and computerized method (endothelial area, EA), and to evaluate their relationships with the prognosis of patients operated on for colorectal adenocarcinoma.

METHODS

Tumoral angiogenesis was studied by means of an immunohistochemical technique, using CD 34, on 126 patients; to quantify the angiogenesis, MVD (defined as number of microvessels per mm(2)) and EA measurement (defined as the area occupied by EA in the microscope field). A computerized method, IMAGELab software was utilized to quantify endothelial area.

RESULTS

The mean number of microvessels was 128.6 MV/mm(2) (SD = 44.5) and the mean EA was 4.3% (SD = 2.1). The Pearson method demonstrated a low correlation coefficient between MVD and EA (r = 0.429). No relationship between MVD and EA was observed with regard to relapse-free interval and overall survival.

CONCLUSION

The histological analysis of angiogenesis expression in patients with colorectal adenocarcinoma can be performed either by computer-assisted image analysis of endothelial area or by conventional microvessels counting. Both methods did not show any significant relationship between these angiogenesis parameters with relapse-free interval and overall survival.

Tumor vascular area correlates with photosensitizer uptake: analysis of verteporfin microvascular delivery in the Dunning rat prostate tumor

The parameters that limit supply of photosensitizer to the cancer cells in a solid tumor were systematically analyzed with the use of microvascular transport modeling and histology data from frozen sections. In particular, the vascular permeability transport coefficient and the effective interstitial diffusion coefficient were quantified for Verteporfin-for-Injection delivery of benzoporphyrin derivative (BPD). Orthotopic tumors had higher permeability and diffusion coefficients (Pd = 0.036 microm/s and D = 1.6 microm(2)/s, respectively) as compared to subcutaneously grown tumors (Pd = 0.025 microm/s and D = 0.9 microm2/s, respectively), likely due to the fact that the vessel patterns are more homogeneous orthotopically. In general, large intersubject and intratumor variability exist in the verteporfin concentration, in the range of 25% in plasma concentration and in the range of 20% for tissue concentrations, predominantly due to these microregional variations in transport. However, the average individual uptake of photosensitizer in tumor tissue was only correlated to the total vascular area within the tumor (R2 = 64.1%, P < 0.001). The data are consistent with a view that microregional variation in the vascular permeability and interstitial diffusion rate contribute the spatial heterogeneity observed in verteporfin uptake, but that average supply to the tissue is limited by the total area of perfused blood vessels. This study presents a method to systematically analyze micro-heterogeneity as well as possible methods to increase delivery and homogeneity of photosensitizer within tumor tissue.

Distinguishing blood and lymph vessel invasion in breast cancer: a prospective immunohistochemical study

Recently, peritumoural (lympho)vascular invasion, assessed on haematoxylin-eosin (HE)-stained slides, was added to the St Gallen criteria for adjuvant treatment of patients with operable breast cancer (BC). New lymphatic endothelium-specific markers, such as D2-40, make it possible to distinguish between blood (BVI) and lymph vessel invasion (LVI). The aim of this prospective study was to quantify and compare BVI and LVI in a consecutive series of patients with BC. Three consecutive sections of all formalin-fixed paraffin-embedded tissue blocks of 95 BC resection specimens were (immuno)histochemically stained in a fixed order: HE, anti-CD34 (pan-endothelium) and anti-D2-40 (lymphatic endothelium) antibodies. All vessels with vascular invasion were marked and relocated on the corresponding slides. Vascular invasion was assigned LVI (CD34 [plus sign in circle] or [minus sign in circle]/D2-40 [plus sign in circle]) or BVI (CD34 [plus sign in circle]/D2-40 [minus sign in circle]) and intra- (contact with tumour cells or desmoplastic stroma) or peritumoural. The number of vessels with LVI and BVI as well as the number of tumour cells per embolus were counted. Results were correlated with clinico-pathological variables. Sixty-six (69.5%) and 36 (37.9%) patients had, respectively, LVI and BVI. The presence of 'vascular' invasion was missed on HE in 20% (peritumourally) and 65% (intratumourally) of cases. Although LVI and BVI were associated intratumourally (P=0.02), only peritumoural LVI, and not BVI, was associated with the presence of lymph node (LN) metastases (p(peri)=0.002). In multivariate analysis, peritumoural LVI was the only independent determinant of LN metastases. Furthermore, the number of vessels with LVI was larger than the number of vessels with BVI (P=0.001) and lymphatic emboli were larger than blood vessel emboli (P=0.004). We demonstrate that it is possible to distinguish between BVI and LVI in BC specimens using specific lymphatic endothelium markers. This is important to study the contribution of both processes to BC metastasis. Furthermore, immunohistochemical detection of lymphovascular invasion might be of value in clinical practice.

Microvessel density and VEGF expression are prognostic factors in colorectal cancer. Meta-analysis of the literature

We performed a meta-analysis of all published studies relating intratumoural microvessel density (MVD) (45 studies) or vascular endothelial growth factor (VEGF) expression (27 studies), both reflecting angiogenesis, to relapse free (RFS) and overall survival (OS) in colorectal cancer (CRC). For each study, MVD impact was measured by risk ratio between the two survival distributions with median MVD as cutoff. Eleven studies did not mention survival data or fit inclusion criteria, six were multiple publications of same series, leaving 32 independent studies for MVD (3496 patients) and 18 for VEGF (2050 patients). Microvessel density was assessed by immunohistochemistry, using antibodies against factor VIII (16 studies), CD31 (10 studies) or CD34 (seven studies). Vascular endothelial growth factor expression was mostly assessed by immunohistochemistry. Statistics were performed for MVD in 22 studies (the others lacking survival statistics) including nine studies (n = 957) for RFS and 18 for OS (n = 2383) and for VEGF in 17 studies, including nine studies for RFS (n = 1064) and 10 for OS (n = 1301). High MVD significantly predicted poor RFS (RR = 2.32 95% CI: 1.39-3.90; P < 0.001) and OS (RR = 1.44; 95% CI: 1.08-1.92; P = 0.01). Using CD31 or CD34, MVD was inversely related to survival, whereas it was not using factor VIII. Vascular endothelial growth factor expression significantly predicted poor RFS (RR = 2.84; 95% CI: 1.95-4.16) and OS (RR=1.65; 95% CI: 1.27-2.14). To strengthen our findings, future prospective studies should explore the relation between MVD or VEGF expression and survival or response to therapy (e.g. antiangiogenic therapy). Assessment of these angiogenic markers should be better standardised in future studies.

CD34 as a marker for evaluating angiogenesis in cervical cancer

CD34 is an antigen present in hematopoietic progenitor cells and endothelial cells. Anti-CD34 antibody is a highly sensitive marker for endothelial cell differentiation and has also been studied as a marker for vascular tumors. However, there are few studies relating it to cervical carcinoma. The aim of this study was to evaluate the association between angiogenesis and the pathoanatomical features of cervical carcinoma using anti-CD34 monoclonal antibody. Sixty-two patients with invasive carcinoma of the uterine cervix in stages Ib-IIa were included. A primary monoclonal antibody specific for CD34 (Anti-Human Hemapoietic Progenitor Cell, CD34 Class II, Clone QBEnd 10, Code M7165, DAKO Corporation) was used in a dilution of 1:25. Microvessel density varied from 4.8 to 20 and was higher in undifferentiated carcinomas (p = 0.03; Mann-Whitney test). Higher microvessel density was associated with squamous cell carcinoma, odds ratio (OR) 8.8 (95% CI: 1.0-76.1), while the presence of lymphatic invasion yielded an OR of 2.6 (95% CI: 0.9-7.4). This study suggested that anti-CD34 antibody reactivity in cervical carcinoma is associated with pathoanatomical features indicative of poorer prognosis.

Translating angiogenesis research into the clinic: the challenges ahead

The field of angiogenesis research has evolved to become one of the most rapidly growing biomedical disciplines. The interest in basic angiogenesis research is sparked by the translational therapeutic potential aimed at developing anti-angiogenesis as a novel therapeutic modality for tumours and a number of non-oncological diseases, such as rheumatoid arthritis, psoriasis, diabetic retinopathy and age-dependent macula degeneration. The molecular determinants of the angiogenic cascade have been characterized in great detail over the last few years. Likewise, intense ongoing efforts are aimed at identifying and validating additional vascular specific determinants that may be exploited as therapeutic targets for pro-angiogenic and anti-angiogenic therapy. At the same time, a large number of angiomodulatory compounds are in various phases of clinical trials. These include the neutralizing vascular endothelial growth factor (VEGF) antibody Avastin, which has successfully passed phase III clinical trials for the combination with chemotherapy in colorectal cancers. In view of the dramatic progress in basic angiogenesis research, surprisingly little is known about the nature of the neovasculature in human tumours. The inclusion and exclusion criteria of clinical trials of anti-angiogenic compounds are devoid of angiogenesis-related parameters and reliable biomarkers to trace the efficacy of an anti-angiogenic intervention are largely missing. Based on a brief review of the biology of the angiogenic cascade, this review provides an overview of the current concepts of the angiogenic vasculature in human tumours and discusses some key unanswered questions in translating angiogenesis research into the clinic.

Determination of tumour prognosis based on angiogenesis-related vascular patterns measured by fractal and syntactic structure analysis

AIMS

Intratumoural micro-vessel density (IMD) has recently been shown to be a valuable prognostic tool in many tumours. Yet, IMD does not take into account the spatial arrangement of the vessels, therefore only partly reflecting the angiogenic situation. In order to describe contextual vascular relationships more accurately, we have used fractal and syntactic structure analysis (SSA) based on computerised image processing to quantify micro-vascular hot spots.

MATERIALS AND METHODS

The parametric performance in prediction of patients' outcome was evaluated by univariate analysis and compared with manually obtained IMDs, whereas an automated K-nearest-neighbour (KNN) classifier searched most discriminative parametric combinations. The method is based on analysis of vascular 'hot-spots' of paraffin-embedded tissue sections of invasive cervical carcinoma, colorectal carcinoma and malignant mesothelioma.

RESULTS

For all three cancers, prediction of prognosis based on SSA yielded in general much higher recognition scores compared with IMD or fractal dimension. Survival of cervical carcinoma was mostly correlated with clinical data, with the vascular permeation being the only parameter with independent value. Prognosis of colorectal carcinoma is best described by SSA, completed with IMD, indicating an inverse correlation of survival time with a more irregular pattern and a slight increase in vessel number. For mesothelioma, we found a strong correlation with SSA and patients' outcome, with two SSA-parameters having independent prognostic value.

CONCLUSIONS

The more accurate angiogenic description obtained with SSA may be useful for further exploitation as a prognosticator in a general diagnostic pathology service.

A study into methodology and application of quantification of tumour vasculature in rectal cancer

The application of new surgical techniques in combination with preoperative radiotherapy has minimised the risk of local recurrence in rectal cancer. However, distant metastasis is still a serious problem after seemingly curative resection in patients with rectal cancer. The present study aimed to evaluate the methodology for quantification and the characteristics of the tumour vasculature in relation to the development of metastasis in patients with rectal cancer. From a large multicentre trial, 88 patients were selected, ensuring a relatively high percentage of metastasis. This selection facilitates the study of tumour vasculature characteristics in relation to metastasis. Vessel number, perimeter and area were assessed at both the invasive front and intratumoural area. Hot-spot and random selections were performed simultaneously. The median of each vessel parameter in the study population was used to separate patients into a low- and high-vessel group. Differences in development of distant metastasis were studied between low- and high-vessel groups. The data of the present study show that only vascular perimeter randomly assessed at the invasive front was associated with distant metastasis. Patients with a high score had a lower distant metastasis rate than patients with a low score (37% and 62%, respectively). High-vessel perimeter was independent of tumor node metastasis staging, but was associated with an increased presence of immune cells, comprising T cells, mast cells, eosinophils and neutrophils. This methodological study on the biological relevance of various vessel characteristics showed that a large vascular endothelial surface, as reflected by a high perimeter, was the only vessel characteristic indicative of improved patient outcome. The underlying principle for this association may be the improved immune response.

The significance of angiogenesis in malignant pheochromocytomas

The purpose of this study was to investigate tumor angiogenesis in a series of benign and malignant pheochromocytomas and to determine whether there is a correlation between angiogenesis and the presence of distant metastases. In this study, the CD31 monoclonal antibody was selected to measure intratumoral microvessel density. Nineteen patients with malignant pheochromocytomas and nineteen patients with benign pheochromocytomas who underwent operation were studied. In order to quantify intratumoral microvessel density, the total number of pixels of CD31-positive reactivity was assessed and expressed as a percentage of the total tissue area in the analyzed field. Analysis of variance revealed a statistically significant correlation between malignancy and intratumoral microvessel density (p = 0.0009). Although there was a considerable variability in the intratumoral microvessel density from tumor to tumor within both the benign and the malignant group, a percentage of more than 28.5% anti-CD31 stained area was found only in malignant tumors. In conclusion, this study shows that the mean intratumoral microvessel density in malignant pheochromocytomas is increased approximately twofold as compared with benign tumors. However, the clinical significance of this prognostic marker is rather weak, because only 4 of the 19 malignant pheochromocytomas had microvessel density higher than this threshold of 28.5%.

Increased microvascular network in bone marrow of HIV-positive haemophilic patients

OBJECTIVES

Angiogenesis has been associated with the pathogenesis of myelodysplastic syndromes (MDSs). However, less is known about the significance of this process in the bone marrow of HIV-positive patients with myelodysplastic features (MDF).

METHODS

Trephines from 22 HIV-positive haemophilic patients were immunostained for CD34 antigen, and the microvessel density (MVD) was quantitatively evaluated and compared with that of 21 biopsies from patients with primary MDS and with that of 12 control bone marrows with no evidence of marrow disease.

RESULTS

Bone marrow MVD in HIV-positive haemophilic patients was similar to that in patients with MDS; however, both groups revealed significantly higher MVD counts than those of control bone marrows (P=0.002). Mean MVD counts of HIV-positive haemophilic patients were significantly associated with HIV RNA levels (P=0.008). In contrast, no correlation was found between MVD and clinical HIV stage or CD4 counts at the time of biopsy.

CONCLUSIONS

These results suggest a direct involvement of HIV in the pathogenesis of MDF in HIV infection. Elucidation of the mechanisms underlying bone marrow angiogenesis in HIV-positive patients may provide further insights into the pathobiology of AIDS.

Analysis of Effective Molecular Diffusion Rates for Verteporfin in Subcutaneous Versus Orthotopic Dunning Prostate Tumors¶

Photosensitizer biodistribution change inside tissue is one of the dominant factors in photodynamic therapy efficacy. In this study, the pharmacokinetics of a benzoporphyrin derivative (BPD), delivered in verteporfin for injection formulation, have been quantified in the rat Dunning prostate tumor MAT-LyLu model, using both subcutaneous and orthotopic sites. Blood plasma sampling indicated that BPD had a bi-exponential metabolic lifetime in vivo, with the two lifetimes being 9.6 min and 8.3 h. The spatial distributions in the tumor were quantified as a function of distance from the perfused blood vessels, using fluorescence histologic images of the tumor. A fluorescent vascular marker was used to obtain locations and shapes of perfused capillaries at a wavelength of emission different from that of BPD and to allow colocalized images to be acquired of vessel and BPD locations. Using the BPD fluorescence images obtained 15 min after intravenous administration, a forward finite-element solution to the diffusion equation was used to predict the drug distribution by matching the fluorescence intensity images observed microscopically. An inverse solver was used to minimize the root mean square error between the image of simulated diffusion and the experimental image, resulting in estimation of the diffusion coefficient of BPD in the tumor models. Effective diffusion coefficients were 0.88 and 1.59 microm2/s for the subcutaneous and orthotopically grown tumors, respectively, indicating that orthotopic tumors have significantly higher vascular extravasation rates as compared with subcutaneous tumors. This analysis supports the hypothesis that leakage rates of the photosensitizer vary considerably. Thus, although varying the time between injection and optical irradiation may be used to vary the targeting between vascular and less vascular areas, the precise time of treatment will depend on the nature of the permeability of the vasculature in the tissue being treated.

Angiogenic switch during 5T2MM murine myeloma tumorigenesis: role of CD45 heterogeneity

The active role of angiogenesis during disease progression is well recognized in solid tumors. In hematologic malignancies such as multiple myeloma (MM), it is not known whether tumor neovascularization is an epiphenomenon or whether it is actively involved in disease progression. At clinical presentation, myeloma disease and the associated angiogenesis are both well established. Here the 5T2MM murine model was used to analyze angiogenesis during preclinical myeloma stages. Bone marrow (BM) of 5T2MM-inoculated mice was analyzed at weekly intervals until the end stage of the disease. Histologic analysis and assessment of microvessel density (MVD) by CD31 staining demonstrated a preangiogenic stage of small tumor aggregates followed by an angiogenic switch and subsequently an angiogenic stage of progressive tumor growth and large, confluent tumor nodules. Flow cytometric analysis that indicated an increase in percentage CD45- MM cells preceded the angiogenic switch. Real-time polymerase chain reaction (RT-PCR) of sorted CD45+ and CD45- MM cells indicated higher vascular endothelial growth factor 120 (VEGF120) and VEGF164 transcripts in CD45- MM cells. VEGF enzyme-linked immunosorbent assay (ELISA) revealed high secretion by CD45- MM cells but no protein secretion by CD45+ MM cells, indicating angiogenic heterogeneity among the MM cells. These data suggest that, like in solid tumors, angiogenic switch and angiogenic heterogeneity exist in MM.

Effect of allogeneic stem cell transplantation on bone marrow angiogenesis in chronic myelogenous leukemia

Increased bone marrow angiogenesis is a poor prognostic marker in patients with chronic myelogenous leukemia (CML). Allogeneic stem cell transplantation (ASCT) can be curative for patients with CML. Studies in myeloma have shown persistent increased bone marrow microvessel density (MVD) after autologous transplantation. It is not clear if abnormal bone marrow angiogenesis persists following a curative intervention like allogeneic transplantation. We evaluated MVD from bone marrow samples obtained just prior to and at 3-5 months after ASCT in 24 patients with CML. The median MVD pre-transplant was 14 (4-37), with 11 patients having high-grade angiogenesis and 13 having low grade. The median post transplant MVD was 20 (range 5-36), with 12 patients having high-grade angiogenesis and 12 low grade. The median time between biopsies was 4 months (range 1-6 months). The microvessels in the post transplant bone marrow appeared morphologically different with striking dilatation and sinusoidal appearance compared to the pre-transplant marrow. However, there was no significant change in MVD following transplant (P=0.8, paired t-test). Abnormal bone marrow angiogenesis appears to persist in the bone marrow following ASCT for CML, at least in the short term.

Increased angiogenesis in the bone marrow of HIV-positive patients with myelodysplasia

AIM

Little is known about the significance of angiogenesis in the bone marrow of HIV-positive patients with myelodysplastic features (MDF). However, this process has been associated with the pathogenesis of primary myelodysplastic syndromes (MDS). The aim of the study was to investigate angiogenesis in the bone marrow of HIV-positive patients.

METHODS

Bone marrow biopsies from 28 HIV-positive patients were immunostained for factor VIII and the microvessel density (MVD) was quantitatively evaluated and compared with that of 32 biopsies from patients with primary MDS and to 18 control bone marrows from patients with no evidence of bone marrow disease.

RESULTS

Bone marrow MVD in HIV-positive patients was similar to that of MDS. However, both groups revealed significantly higher MVD counts compared to those of control bone marrows (MDF vs controls P=0.022, MDS vs controls P=0.001).

CONCLUSIONS

Bone marrow from HIV-positive patients with MDF reveals similar microvessel counts compared to those with primary MDS, although both differ significantly from that of control bone marrow. Elucidation of the mechanisms underlying bone marrow angiogenesis in HIV-positive patients, may provide further insights into the pathobiology of AIDS and might be of value for the development of new therapeutic strategies for this disease.

Vascular patterns in reactive lymphoid tissue and in non-Hodgkin's lymphoma

The few studies published on angiogenesis in lymphoma have raised the question of whether or not microvessel density (MVD) is associated with more aggressive disease and have reported the observation that in follicular lymphomas, vessels are mature rather than immature. We investigated MVD and the vascular phenotype within follicular or diffuse large B-cell lymphomas, reactive nodes and tonsils. Vascular phenotype was defined by the expression or loss of reactivity to the antibody LH39 (detecting the LH39 laminin epitope of the basement membrane in mature vessels) and by detection of alpha V beta 3 (expressed on immature vessels). In reactive nodes and in follicular lymphomas, MVD was higher in the paracortex than in germinal centres or in neoplastic follicles. However, in neoplastic follicles an increase in alpha V beta 3-positive endothelium suggested the activation of an angiogenic pathway different from that present in the reactive follicles. In large B-cell lymphomas, MVD was higher than in reactive and neoplastic follicles but lower than in the reactive paracortex. The number of immature vessels (LH39 negative) and of alpha V beta 3-positive vessels was higher than in reactive lymph nodes and follicular lymphoma suggesting that a switch to a different angiogenic pathway has occurred. Finally, we have demonstrated that within reactive and neoplastic follicles vascular regression is occurring, perhaps constraining the growth of reactive follicles alongside other phenomena such as apoptosis. Vascular regression was previously believed to occur in adults only in ovarian and endometrial tissue. We conclude that different types of angiogenesis are present in follicular lymphomas and large B-cell lymphomas. This has implications for possible future therapies.

Angiogenesis and invasive recurrence in ductal carcinoma in situ of the breast

The development of an invasive recurrence following treatment for ductal carcinoma in situ (DCIS) converts a non-fatal disease to one associated with mortality. To date, no pathological or molecular features have been found to predict for the type of recurrence. Previous studies have suggested that in DCIS angiogenesis may be an important factor in determining the transformation from in situ to invasive carcinoma. We looked at 355 cases of DCIS and found that 32 had subsequently developed recurrent disease. In these 32 cases and in matched controls, periductal vascular density was determined using morphometry and anti-endothelial antibodies, von Willebrand factor (vWF) and CD34. Vascular density was related to the risk of both invasive and in situ recurrence. Normal lobules at least 2 mm away were used as controls. Differences in the phenotype of individual blood vessels was detected by performing dual staining immunofluorescence on selected cases. The microvessel density (MVD), as detected with the CD34 antibody, was higher around foci of DCIS than around normal breast lobules (P=0.001). Furthermore, it was significantly higher in cases of DCIS that recurred (P<0.0001). The findings with the vWF antibody were less clear cut and suggested a trend in decreasing MVD with increasingly aggressive disease. Dual immunofluorescence staining shows that the increase in MVD seen around DCIS is due to an increase in CD34+/vWF-blood vessels. An increase in CD34+/vWF-of blood vessels may be able to predict cases of DCIS that are at a high risk of developing a recurrence.

Angiogenesis and hepatic colorectal metastases

Angiogenesis is a critical step in the metastatic cascade of colorectal cancer. Several angiogenesis inhibitors have been evaluated in animal models and have shown efficacy, but challenges remain in using these drugs effectively in the clinical setting. Although several of these angiogenesis inhibitors are currently being evaluated in clinical trials, alone or in combination with cytotoxic chemotherapy, early results suggest that angiogenesis inhibitors alone, when used for advanced disease, have minimal activity. It is likely that this class of drugs will prove more efficacious when used either in the setting of minimal disease as agents that may promote tumor dormancy or in combination with other conventional forms of therapy. In addition, strategies such as metronomic therapy have been proposed whereby lower doses of cytotoxic chemotherapy, given more frequently, may act via an antiangiogenic mechanism [67,68]. Another challenge is identifying methods of assessing response to antiangiogenic therapy. To date, traditional methods of identifying response to treatment have not proven effective. Several investigators are working toward identifying circulating endothelial or tumor-associated factors that may be useful in following treatment. Novel imaging techniques are also being evaluated with enhanced CT and MRI, and newer modalities. Hepatic colorectal metastases provide an opportune setting in which to accomplish these challenges because the high incidence of disease and the ability to measure tumor with a variety of techniques lend themselves to evaluation of antiangiogenic therapy.

Bone marrow angiogenesis in multiple myeloma: effect of therapy

Recent studies have demonstrated that angiogenesis has a role in haematological malignancies, including multiple myeloma. Multiple myeloma is characterized by inevitable relapse after standard or high-dose chemotherapy. To study the effect of chemotherapy on bone marrow angiogenesis in patients with multiple myeloma, we used two methods to evaluate bone marrow angiogenesis in patients with newly diagnosed multiple myeloma, comparing these findings with those from bone marrow obtained after standard chemotherapy. Before therapy, an increased degree of bone marrow angiogenesis and a high bone marrow plasma cell labelling index (PCLI) were predictive of poorer survival. As estimated by microvessel density (MVD), the median survivals for patients with low-grade, intermediate-grade and high-grade angiogenesis were 77, 30 and 14 months respectively. After therapy, the MVD did not change significantly. However, when patients with at least a partial response were considered separately, they showed a decrease in MVD. Post-therapy PCLI was predictive of survival, but post-therapy MVD was not. There was good correlation between angiogenesis estimated by visual grading and that determined by MVD assessment. We conclude that the degree of bone marrow angiogenesis is a prognostic marker in patients with multiple myeloma and does not decrease significantly after therapy.

Angioarchitecture of primary oral malignant melanomas

Angiogenesis is an essential process in the progression of malignant tumors. However, little is known of the angioarchitecture in primary oral malignant melanoma. We sought to determine this by the use of periodic acid-Schiff (PAS) stain, endothelial markers (CD34, CD105) and laminin, and by transmission electron microscopy in two cases. The results demonstrated that endothelium-lined vessels dominated the tumor microvasculature and these stained positively for PAS, laminin, and endothelial markers. Mosaic and tumor-lined vessels were infrequently encountered. Most PAS-positive patterned networks and loops ultrastructurally represented intratumor microhemorrhages that probably arose secondary to tumor vessel leakiness. Vascular channels of the vasculogenic mimicry type were rare. They stained for laminin but not for endothelial markers.

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.

Thalidomide as an anti-cancer agent

Thalidomide is a glutamic acid derivative initially introduced as a sedative hypnotic nearly forty years ago. It was withdrawn following numerous reports linking it to a characteristic pattern of congenital abnormalities in babies born to mothers who used the drug for morning sickness. It has gradually been re-introduced into clinical practice over the past two decades, albeit under strict regulation, since it was found to be useful in the management of erythema nodosum leprosum and HIV wasting syndrome. Recognition of its anti-angiogenic effect led to its evaluation in the treatment of various malignancies, where angiogenesis has been shown to play an important role. Numerous clinical trials done over the past four years have confirmed the significant anti-myeloma activity of this drug. It has also shown promise in preliminary trials in the treatment of a variety of different malignant diseases. The mechanisms of its antineoplastic effects continue to be the focus of ongoing research. It has become clear that even though its anti angiogenic effects play a significant role in the anti-tumor activity, there are other properties of this drug which are responsible as well. It also possesses anti-TNF alpha activity, which has led to its evaluation in several inflammatory states. In this concise review, we briefly describe the historical background and pharmacological aspects of this drug. We have concisely reviewed the current knowledge regarding mechanisms of its anti-neoplastic activity and the results of various clinical trials in oncology.

Vascular density and phenotype around ductal carcinoma in situ (DCIS) of the breast

Up to 50% of recurrences of ductal carcinoma in situ of the breast are associated with invasive carcinoma but no pathological or molecular features have yet been found to predict for the development of invasive disease. For a tumour to invade, it requires the formation of new blood vessels. Previous studies have described a vascular rim around ducts involved by ductal carcinoma in situ, raising the possibility that the characteristics of periductal vascularisation may be important in determining transformation from in situ to invasive disease. Periductal vascular density and phenotype were determined using morphometry and a panel of anti-endothelial antibodies (von Willebrand factor, CD31, CD141 and CD34) and related to the presence of invasive carcinoma and other histological features. Compared to normal lobules, pure ductal carcinoma in situ exhibited a greater density of CD34+ and CD31+ vessels but a decrease in those that were immunopositive for vWF, indicating a difference in phenotype and in density. Ductal carcinoma in situ associated with invasive carcinoma showed a profile of vascular immunostaining similar to that of pure ductal carcinoma in situ but there were significantly greater numbers of CD34+ and CD141+ vessels and fewer staining for vWF. There was a significant negative correlation between vascular density and both the cross-sectional areas of the ducts involved and the extent of the necrosis of the tumour they contained. A correlation between vascular density and nuclear grade was also noted, being highest in the intermediate grade. The greater density of CD34+ and CD141+ vessels around ductal carcinoma in situ associated with invasive carcinoma could reflect a greater predisposition to invade but a direct effect of co-existent invasive carcinoma cannot entirely be ruled out in the present study. The relationship between vascular density, grade, duct size and nuclear grade suggests that periductal angiogenesis increases with tumour growth rate but is unable to keep pace with the most rapidly growing lesions.

Tumor angiogenesis in lymph node-negative rectal cancer: correlation with clinicopathological parameters and prognosis

BACKGROUND

Intratumoral microvessel density (MVD) could be used as a prognostic factor in colorectal cancer. We retrospectively analyzed the value of microvessel count in predicting the clinical outcome of stage I and II (Dukes A and B) rectal cancer patients.

METHODS

Eighty-four patients who had undergone curative resection of lymph node-negative rectal cancer were included. Tumor type and differentiation, the depth of local invasion, venous invasion, the character of the invasive margin, and the degree of lymphocytic infiltration were evaluated for each tumor specimen. Immunohistochemical staining for the CD31 endothelial antigen was performed to highlight the microvessels.

RESULTS

The median value of MVD was 45 microvessels. Low MVD (microvessels < or = 45) was observed in 41 patients (48.8%), and high MVD (>45) was found in 43 (51.2%). The presence of conspicuous lymphocytic infiltration was significantly associated with increased vessel density. With uni- and multivariate survival analysis MVD did not show any prognostic significance. The character of the invasive margin was the only parameter with independent prognostic value.

CONCLUSIONS

MVD does not seem to provide any additional prognostic information when compared with standard histopathological parameters in lymph node-negative rectal cancer. It is likely that the strong association between MVD and the presence of conspicuous lymphocytic infiltration may interfere with its predictive value.

Prognostic evaluation of the microvascular network in myelodysplastic syndromes

Considering the recently stated suggestion of neovascularization being implicated in myelodysplastic syndromes (MDS) pathogenesis, we evaluated multiple morphometric microvascular characteristics in MDS, in relation to clinicopathologic factors and prognosis. Trephines from 50 newly diagnosed MDS patients were immunostained for factor VIII and compared to those from 20 controls, 10 chronic myelomonocytic leukemia (CMML) and 12 acute myeloid leukemia (AML) patients. Quantitation of microvessel density (MVD), area, total vascular area (TVA), major and minor axis length, perimeter, compactness, shape factor, Feret diameter, and the number of branching vessels was performed by image analysis. Overall, the MDS group had significantly higher MVD, TVA, minor axis and shape factor values and significantly lower compactness than the control group. AML was characterized by increased vascularity compared to MDS and CMML, as well as by the presence of flattened microvessels (lower values of shape factor). Hypercellular MDS showed higher MVD. RA/RARS displayed larger caliber vessels than RAEB, which explains the favorable prognostic effect of increased size-related parameters on progression and/or survival. Moreover, decreased compactness and MVD were independent predictors of longer progression-free survival. It is concluded that angiogenesis is involved in the conversion of normal marrow to MDS and ultimately to AML and that disease progression within MDS is accompanied by qualitative alterations of the microvascular network. Furthermore, size-related parameters affect survival, while shape-related parameters and MVD are more influential with regard to progression-free survival.

Contrast-enhanced color Doppler sonography of uveal melanomas

PURPOSE

The purpose of our study was to evaluate the use of the galactose microbubble-based contrast agent Levovist in color Doppler sonography of uveal melanomas. We also evaluated the use of the resistance index and pulsatility index in differentiating tumor-associated vessels from normal vessels in patients with uveal melanomas.

METHODS

In this prospective study, 40 patients with uveal melanoma were examined with color Doppler sonography before and after the administration of the contrast agent Levovist. The Doppler signals were recorded from both the tumor and the orbit and were evaluated quantitatively and qualitatively.

RESULTS

Tumor-associated vessels were detected without contrast enhancement in 36 of 40 patients and with contrast enhancement in 38 of 40 patients. The spectral characteristics of the Doppler signals did not change after the injection of Levovist. There were no differences-qualitative or quantitative-in Doppler signals between normal and tumor-associated vessels.

CONCLUSIONS

The injection of Levovist slightly improved the detection of small vessels in uveal melanomas and the orbit but did not help to differentiate between normal vessels and tumoral vessels. The differentiation of a solid tumor from subretinal hemorrhage or effusion was improved.

Prognostic significance of microvascular counts in rectal carcinoma

Numerous studies of many tumor types have demonstrated that microvessel quantitation as a measure of angiogenesis is a powerful prognostic tool. Vascular enumeration has been claimed to be an independent prognosticator for several human tumors, including breast carcinoma, melanoma or bladder carcinoma; however, the studies of colorectal cancer have rendered variable results. To test the prognostic influence of this factor in our patients, we selected 39 patients with rectal carcinoma Dukes' stages A to C treated only with curative surgery, with no further adjuvant therapy. The minimal follow-up time was 5 years (60 months). After immunostaining with CD34, we performed a manual count of the vessels following Gasparini's criteria. In our series, vascular enumeration has been a prognosticator for OS (overall survival) but not for RFS (relapse-free-survival) at all Dukes' stages in the univariate analysis. This prognostic influence was lost in the multivariate analysis, in which only stage as well as vascular and neural invasion behaved as significant independent prognosticators. The presence of hypervascularization did not show any significant association with histologic grade, tumor staging, and vascular or neural invasion.

Diffusion limited hypoxia estimated by vascular image analysis: comparison with pimonidazole staining in human tumors

PURPOSE

To assess diffusion limited hypoxia in human tumors using image analysis of vasculature and to compare it with the bioreductive marker pimonidazole as an independent method.

MATERIALS AND METHODS

To set up the method, nine rectal adenocarcinomas and ten squamous cell carcinomas were analyzed. To validate the method, ten squamous cell carcinomas of the cervix were analyzed from patients who were injected with pimonidazole and biopsied approximately 24 h later. Sections of the rectal and esophageal tumors were stained for vasculature, while cervix tumor sections were double stained for vasculature and pimonidazole. Tumor areas were delineated on digitized images, and the proportion of tumor tissue greater than a fixed distance from the nearest blood vessel (called diffusion limited fraction, DLF) was then calculated. The proportion of tumor area stained for pimonidazole was also measured.

RESULTS

There was a wide variation between tumors in both the vascular-derived DLF and in the pimonidazole-stained fraction. Average DLFs varied between 1.5 and 92% for different tumors, with significant differences between them. The area stained by pimonidazole was significantly smaller than DLF for all tumors. The correlation between pimonidazole area and DLF was significant in three of seven tumors containing > or = 3 images. When images from all tumors (n=123) were analyzed together, the correlation was highly significant (r=0.47, P<0.0001).

CONCLUSION

The vascular derived DLF correlates significantly with pimonidazole staining, but there was large scatter. Both methods may underestimate perfusion limited hypoxia.

Increased angiogenesis in the bone marrow of patients with acute myeloid leukemia

The importance of angiogenesis for the progressive growth and viability of solid tumors is well established. In contrast, only few data are available for hematologic neoplasms. To investigate the role of angiogenesis in acute myeloid leukemia (AML), bone marrow biopsies from 62 adults with newly diagnosed, untreated AML (day 0) were evaluated. Further studies were done after the completion of remission induction chemotherapy (day 16 of induction chemotherapy, n = 21; complete remission, n = 20). Microvessels were scored in at least 3 areas (×500 field, 0.126 mm2) of the highest microvessel density in representative sections of each bone marrow specimen using immunohistochemistry for von Willebrand factor and thrombomodulin. Microvessel counts were significantly higher in patients with AML (n = 62) compared with control patients (n = 22): median (interquartile range) 24.0 (21.0-27.8)/×500 field vs 11.2 (10.0-12.0)/×500 field, respectively (P < .001). On day 16 of induction chemotherapy, microvessel density was reduced by 60% (44-66) (P < .001) in hypoplastic marrows without residual blasts, in contrast to only 17% (0-37) reduction in hypoplastic marrows with ≥ 5% residual blasts (P < .001 for the difference between both groups). Bone marrow biopsies taken at the time of complete remission displayed a microvessel density in the same range as the controls. In conclusion, there is evidence of increased microvessel density in the bone marrow of patients with AML, which supports the hypothesis of an important role of angiogenesis in AML. Furthermore, these findings suggest that antiangiogenic therapy might constitute a novel strategy for the treatment of AML.

Increased angiogenesis in the bone marrow of patients with acute myeloid leukemia

The importance of angiogenesis for the progressive growth and viability of solid tumors is well established. In contrast, only few data are available for hematologic neoplasms. To investigate the role of angiogenesis in acute myeloid leukemia (AML), bone marrow biopsies from 62 adults with newly diagnosed, untreated AML (day 0) were evaluated. Further studies were done after the completion of remission induction chemotherapy (day 16 of induction chemotherapy, n = 21; complete remission, n = 20). Microvessels were scored in at least 3 areas (×500 field, 0.126 mm2) of the highest microvessel density in representative sections of each bone marrow specimen using immunohistochemistry for von Willebrand factor and thrombomodulin. Microvessel counts were significantly higher in patients with AML (n = 62) compared with control patients (n = 22): median (interquartile range) 24.0 (21.0-27.8)/×500 field vs 11.2 (10.0-12.0)/×500 field, respectively (P &lt; .001). On day 16 of induction chemotherapy, microvessel density was reduced by 60% (44-66) (P &lt; .001) in hypoplastic marrows without residual blasts, in contrast to only 17% (0-37) reduction in hypoplastic marrows with ≥ 5% residual blasts (P &lt; .001 for the difference between both groups). Bone marrow biopsies taken at the time of complete remission displayed a microvessel density in the same range as the controls. In conclusion, there is evidence of increased microvessel density in the bone marrow of patients with AML, which supports the hypothesis of an important role of angiogenesis in AML. Furthermore, these findings suggest that antiangiogenic therapy might constitute a novel strategy for the treatment of AML.

Openings between defective endothelial cells explain tumor vessel leakiness

Leakiness of blood vessels in tumors may contribute to disease progression and is key to certain forms of cancer therapy, but the structural basis of the leakiness is unclear. We sought to determine whether endothelial gaps or transcellular holes, similar to those found in leaky vessels in inflammation, could explain the leakiness of tumor vessels. Blood vessels in MCa-IV mouse mammary carcinomas, which are known to be unusually leaky (functional pore size 1.2-2 microm), were compared to vessels in three less leaky tumors and normal mammary glands. Vessels were identified by their binding of intravascularly injected fluorescent cationic liposomes and Lycopersicon esculentum lectin and by CD31 (PECAM) immunoreactivity. The luminal surface of vessels in all four tumors had a defective endothelial monolayer as revealed by scanning electron microscopy. In MCa-IV tumors, 14% of the vessel surface was lined by poorly connected, overlapping cells. The most superficial lining cells, like endothelial cells, had CD31 immunoreactivity and fenestrae with diaphragms, but they had a branched phenotype with cytoplasmic projections as long as 50 microm. Some branched cells were separated by intercellular openings (mean diameter 1.7 microm; range, 0.3-4.7 microm). Transcellular holes (mean diameter 0.6 microm) were also present but were only 8% as numerous as intercellular openings. Some CD31-positive cells protruded into the vessel lumen; others sprouted into perivascular tumor tissue. Tumors in RIP-Tag2 mice had, in addition, tumor cell-lined lakes of extravasated erythrocytes. We conclude that some tumor vessels have a defective cellular lining composed of disorganized, loosely connected, branched, overlapping or sprouting endothelial cells. Openings between these cells contribute to tumor vessel leakiness and may permit access of macromolecular therapeutic agents to tumor cells.

Vascular enumeration as a prognosticator for colorectal carcinoma

Vascular enumeration is thought to be an independent prognosticator for several human tumours, including breast, bladder and colorectal carcinomas. There have been 12 reports on the prognostic influence of vascular enumeration in colorectal carcinoma with different results. To test the prognostic influence of this factor in our patients, we have selected 126 patients with colorectal carcinoma Dukes' stages A to C treated only with curative surgery with no further adjuvant therapy. The minimal follow-up time was 5 years (60 months). After immunostaining with CD34, we performed a manual count of the vessels following Gasparini's criteria. In our series vascular enumeration showed significant association with the histological grade (P = 0.03) with a cut-off point at 77 vessels/200x, but not with tumour staging and vascular and neural invasion (P > 0.05). Vascular enumeration was a prognosticator for RFS (relapse-free survival) (P = 0.009) and OS (overall survival) (P = 0.01) in all Dukes' stages in the univariate analysis, but this prognostic influence was lost in the multivariate analysis, in which only stage, histological differentiation, location and vascular and neural invasion behaved as significant independent prognosticators.

Pharmacokinetics and bioavailability of oral 5'-deoxy-5-fluorouridine in cancer patients

AIMS

Oral administration of 5-fluorouracil (FUra), an important cytotoxic agent, is limited by a wide variation in bioavailability. 5'-deoxy-5-fluorouridine (dFUrd), a masked form of FUra, has shown promise clinically when given intravenously or orally as a solution or tablet. This study investigates the efficacy of an oral capsule formulation of dFUrd in generating continuous systemic levels of this compound in cancer patients.

METHODS

Six patients with advanced intestinal or ovarian malignancies were given three cycles of dFUrd, days 1-5, at intervals of 4 weeks. The doses of dFUrd were 600 mg m-2 three times daily, 800 mg m-2 three times daily, and 1000 mg m-2 three times daily, on cycles one, two and three, respectively (total dose 36 g m-2 ). The initial dose in each cycle was given as a slow intravenous injection over 10 min, and the remainder orally. Plasma and urine levels of dFUrd and two of its metabolites, FUra and 5,6-dihydro-5-fluorouracil (FUraH2 ), were monitored in six patients at each dose level.

RESULTS

All six patients completed the study, receiving three different doses over a 3 month period, following which one had achieved a partial response, one had stable disease, and four had developed progressive disease. Side-effects were negligible, and only two instances of transient diarrhoea WHO grade 1 were seen. Total body clearance (CLtot) of intravenous dFUrd decreased with increasing dose; 2.7, 2.0 and 1.3 l min-1 m-2, following doses of 600, 800 and 1000 mg m-2, respectively. The mean elimination half-life of intravenous dFUrd increased with the dose from 15 to 22 min. Oral dFUrd was rapidly absorbed with a lag time of less than 20 min. The mean elimination half-life (t1/2, z ) of oral dFUrd was 32-45 min in the dose range 600-1000 mg m-2. The AUC of FUra and FUraH2 increased overproportionally with increasing intravenous doses of dFUrd. The mean systemic bioavailability of oral dFUrd was 34-47%.

CONCLUSIONS

dFUrd, which selectively releases the antimetabolite FUra in tumour cells, can be given orally at doses of 600-1000 mg m-2 three times daily for 5 days. The systemic levels achieved are equivalent to those seen following continuous infusions of dFUrd or FUra. Toxicity is tolerable, and further clinical investigation of oral dFUrd is warranted.

Prospective study of intratumoral microvessel density, p53 expression and survival in colorectal cancer

Adjuvant treatment of patients with colorectal cancer is hampered by a lack of reliable prognostic factors in addition to the clinicopathological staging system. A poorly defined but considerable fraction of Astler-Coller stage B patients will experience tumour recurrence, and some of the stage C patients will probably survive for a prolonged time after surgery without adjuvant treatment. Assessing parameters related to tumour angiogenesis has provided valuable prognostic information in different tumour types. The formation of new microvessels is part of the malignant phenotype in the majority of tumours. Alterations in tumour-suppressor genes, such as the p53 gene, or oncogenes, such as the ras gene, have been found to be responsible for changing the local balance of pro- and antiangiogenic factors in favour of the former. In this prospective study, intratumoral microvessel density (IMD) was assessed by immunostaining tissue sections for CD31 and counting individual microvessels in selected and highly vascular regions in specimens of 145 colorectal cancer patients. p53 protein overexpression was semiquantitatively determined after immunohistochemistry. In both uni- and multivariate analysis, high IMD was significantly associated with shorter survival in the patients undergoing surgery with curative intent (Astler-Coller stages A-C). p53 added prognostic power to IMD, both in Astler-Coller stage B and stage C patients. An association between IMD and mode of metastasis was also noted. High IMD was strongly associated with the incidence of haematogenous metastasis during follow-up, but not with the presence of lymphogenic metastasis observed at surgery. This study confirms the results of previous retrospective analyses of IMD and survival in colorectal cancer and warrants a clinical validation by randomizing stage B tumour patients with high IMD and p53 overexpression between adjuvant treatment or not.

Overexpression of CD44: a useful independent predictor of prognosis in patients with colorectal carcinomas

BACKGROUND

The goal was to investigate the potential correlation between overexpression of CD44, high microvessel count (MVC), and p21ras with length of relapse-free and overall survival in patients with colorectal adenocarcinomas.

METHODS

CD44, factor VIII-related antigen (FVIII-RA), and p21ras were localized immunohistochemically in patients with colorectal adenomatous polyps (n = 8) and adenocarcinomas (n = 98). The correlation between the expression of CD44, MVC in the areas with highest density, and p21ras with relapse-free and overall survival time was investigated. Data were analyzed statistically using univariate and multivariate systems.

RESULTS

In patients with adenomatous polyps, the positivity of CD44, FVIII-RA, and p21ras was 75%, 62%, and 88%, respectively. In patients with colorectal carcinomas the positivity of CD44 was 55%, and for p21ras it was 52%. The median of FVIII-RA was 4 MVC (range, 0.0 to 32.33). MVC was greater than 4 in 53% of the patients with colorectal carcinomas. In univariate analysis, a significantly longer relapse-free time (CD44: P = .0004; FVIII-RA: P = .0006) and overall survival time (CD44: P = .0001; FVIII-RA: P = .001) were observed for patients with CD44-negative tumors and MVC below 4 as compared to those with CD44-positive tumors and MVC greater than 4. Similar observations were noted in patients with Dukes B and C disease and the rectum as the site of tumor. In multivariate analysis, only CD44 correlated significantly with both relapse-free (P = .0003) and overall survival (P = .00001).

CONCLUSION

Univariate analysis showed CD44 and MVC to be independent predictors of prognosis in colorectal carcinomas. Multivariate analysis showed that CD44 positivity was the most important indicator of an unfavorable prognosis for relapse-free and overall survival in patients with colorectal cancer. Thus, it can be deduced that whether CD44 is positive or negative in patients with colorectal cancer may have prognostic importance and in the future may be used as a factor in the pathologic evaluation of tumor specimens. This hypothesis needs to be tested prospectively in a larger number of patients.

Quantitative analysis of basic fibroblast growth factor and vascular endothelial growth factor in human colorectal cancer

Tumour growth is angiogenesis dependent. Some authors suggest a prognostic role of microvessel count in colorectal cancer. We tested the role of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) in the switch to the angiogenic phenotype in 35 patients with colorectal cancer at different stages of disease. We evaluated the two angiogenic factors, by enzyme-linked immunosorbent assay (ELISA), in tumour, peritumoral mucosa, pathological mesenteric and peripheral blood. We used ten endoscopic intestinal biopsies and ten peripheral blood samples from healthy subjects as control. bFGF was significantly lower in tumour tissues and in peritumoral mucosas than in healthy mucosas, whereas VEGF was up-regulated in tumours but not in peritumoral mucosa. Both angiogenic factors were greatly increased in mesenteric blood. VEGF tumour and serum levels were significantly correlated with the stage of disease. bFGF tumour and serum concentration were not correlated with the stage of disease. The high levels of bFGF in mesenteric blood suggest that this growth factor might be abnormally released from tumour tissue and peritumoral mucosa and could function as an early effector in the switch to the angiogenic phenotype. In contrast, VEGF, whose levels show a significant correlation with the stage of disease, could act in a following step, supporting tumour progression.

Evaluation of tumour angiogenesis as a prognostic marker in malignant mesothelioma

Angiogenesis plays an important role in the growth, progression, and metastasis of solid tumours. Malignant mesothelioma (MM) of the pleura is a highly invasive tumour with a poor prognosis. In the present study, microvascular quantification was undertaken on 25 specimens of mesothelioma and 15 specimens of non-neoplastic mesothelium (NNM), by staining for the antigens CD34 and CD31. Areas of highest intratumoural microvascular density (IMD) were identified and counted either manually (mIMD) or on a computerized image analysis system (CIAS; iIMD). The two IMDs were significantly correlated with each other (r = 0.736; P < 0.001). The average IMD for MM was significantly (P < 0.001) higher than in NNM. Moreover, each unit increment in iIMD for MM, when regarded as a continuous variable, was significantly (P = 0.001) associated with an increased hazard of about 4 per cent. When regarded as a categorical variable, the patients in the highest tertile (> 58 vessels/field) had a significantly (P < 0.01; log-rank test) shorter survival than patients in the lowest tertile (< 45 vessels/field). This association was independent of the age of the patient and of the histological type or grade of the MM. No association was noted with p53 immunoexpression. Although the mean vascular area of blood vessels measured on the CIAS did not correlate with survival, assessment of IMDs can be an important independent prognostic indicator in malignant mesothelioma.

Microvessel density in core biopsies of prostatic adenocarcinoma: a stage predictor?

Microvessel density was recently reported to be an independent correlate of tumour stage in whole mount prostatectomy specimens. This prompted an investigation of whether the quantitation of tumour microvessels could also be reliably applied to prostatic core biopsies, as a presurgical determinant of local tumour extension. The study was performed on a series of 46 unselected patients with prostatic adenocarcinomas undergoing radical prostatectomy. Intratumoural microvasculature was highlighted immunohistochemically using an antibody against CD31 and subsequently evaluated at x 400 magnification in both biopsies and corresponding prostatectomies. The highest microvessel count was reported for each case. Ten cases (22 per cent) had to be excluded because of insufficient measurable tumour areas in core biopsies. The remaining 36 cases (16 pT2; 20 pT3) showed a high degree of correlation between microvessel density in biopsies and prostatectomies (P < 0.0001). Similarly, pre- and post-operatively determined microvascular counts correlated well with tumour stage (P < 0.0001). Furthermore, the median microvessel density in core biopsies and tumours, i.e., 34, distinguished well between organ-confined and organ-extending tumours (positive predictive value for pT3 tumours 94.4 per cent; sensitivity 85 per cent). These data indicate that the evaluation of microvessels in core biopsies, eventually combined with other parameters, could be a reliable method for the individual prediction of the post-surgical tumour stage of prostatic adenocarcinoma.

Glutamine extraction by the gut is reduced in depleted [corrected] patients with gastrointestinal cancer

OBJECTIVE AND SUMMARY BACKGROUND DATA

Glutamine is an important fuel for the intestinal mucosa. However, glutamine pools may become depleted in the cancer-bearing host as a result of tumor consumption and diminished production due to nutritional depletion. As human data are lacking, the authors investigated glutamine extraction by different sites of the human intestine, including tumor and the potential relation with the degree of nutritional depletion.

METHODS

Thirty-two patients with gastrointestinal malignancies were studied. Blood from an artery and veins draining jejunum, ileum, colon, or tumor were sampled. Depletion was estimated by the percentage ideal body weight.

RESULTS

Fractional glutamine extraction rate in the jejunum was 24%, three times higher than in ileum and colon. Percentage ideal body weight correlated with arterial glutamine levels (r = 0.5275, p = 0.003). In addition, arterial glutamine concentrations were correlated with extraction in the ileum (r = -0.8411, p < 0.001). Colon-containing tumor did not extract more glutamine than did nontumor-containing colon.

CONCLUSIONS

Glutamine is a quantitatively more important substrate for the proximal intestine than for the distal gut. Nutritional depletion results in decreased arterial glutamine concentration, which in turn results in diminished extraction. Colon cancer does not function as a glutamine trap and does not contribute to glutamine depletion.

Influence of investigator experience and microscopic field size on microvessel density in node-negative breast carcinoma

In this study on the determination of intratumoral microvessel density (MVD) in breast cancer, we have investigated the influence of the observer experience and the microscopic field size. We have used the sample set reported on earlier in the J Natl Cancer Inst 87: 1797-1798, 1995. This case-control study has shown a positive association of high MVD and unfavorable outcome when comparing node-negative pT1-2 breast carcinoma (NNBC) patients with a disease-free period of over ten years with those with an early distant relapse. Tumor sections of both outcome groups (favorable: n = 19; unfavorable: n = 19) were immunostained for factor VIII related-antigen (FVIII r-Ag). Microvessels were counted in the areas of most intense vascularization ('hot spots'), both at magnification x 200 (field size of 0.61 square mm) and x 400 (field size of 0.15 square mm), by one inexperienced and three experienced observers. Microphotographs of individual vascular hot spots were analyzed using overlays resembling the two field sizes. The main results obtained are: i) a confirmation of the prognostic value of microvessel density in the case-control sample set (n = 38) was established by all experienced but not by the unexperienced investigator; ii) both at x 200 and x 400 magnification, angiogenesis quantification in vascular hot spots contained prognostic information. The results of this study indicate that the selection of vascular hot spots in tumor sections immunostained for an antigen expressed on endothelial cells is more prone to inter-observer variability and more dependent on training than the counting of the microvessels within predefined hot spots itself. The microscopic magnification and resulting field size do not influence the prognostic significance of MVD in NNBC. This information validates the development of more objective methods of measuring the amount of angiogenesis within malignant tissue. This will allow more accurate implementation of the angiogenesis parameter in multiparametric and prospective prognostic factor studies in NNBC.