Relationship between vascularity, age and survival in non-small-cell lung cancer

Host-Related Factors as Targetable Drivers of Immunotherapy Response in Non-Small Cell Lung Cancer Patients

Despite some significant therapeutic breakthroughs leading to immunotherapy, a high percentage of patients with non-small cell lung cancer (NSCLC) do not respond to treatment on relapse, thus experiencing poor prognosis and survival. The unsatisfying results could be related to the features of the tumor immune microenvironment and the dynamic interactions between a tumor and immune infiltrate. Host-tumor interactions strongly influence the course of disease and response to therapies. Thus, targeting host-associated factors by restoring their physiologic functions altered by the presence of a tumor represents a new therapeutic approach to control tumor development and progression. In NSCLC, the immunogenic tumor balance is shifted negatively toward immunosuppression due to the release of inhibitory factors as well as the presence of immunosuppressive cells. Among these cells, there are myeloid-derived suppressor cells, regulatory T cells that can generate a tumor-permissive milieu by reprogramming the cells of the hosts such as tumor-associated macrophages, tumor-associated neutrophils, natural killer cells, dendritic cells, and mast cells that acquire tumor-supporting phenotypes and functions. This review highlights the current knowledge of the involvement of host-related factors, including innate and adaptive immunity in orchestrating the tumor cell fate and the primary resistance mechanisms to immunotherapy in NSCLC. Finally, we discuss combinational therapeutic strategies targeting different aspects of the tumor immune microenvironment (TIME) to prime the host response. Further research dissecting the characteristics and dynamic interactions within the interface host-tumor is necessary to improve a patient fitness immune response and provide answers regarding the immunotherapy efficacy, with the aim to develop more successful treatments for NSCLC.

Migration Stimulating Factor (MSF): Its Role in the Tumour Microenvironment

Migration Stimulating Factor (MSF) is a 70 kDa truncated isoform of fibronectin (FN); its mRNA is generated from the FN gene by an unusual two-stage processing. Unlike full-length FN, MSF is not a matrix molecule but a soluble protein which displays cytokine-like activities not displayed by any other FN isoform due to steric hindrance. There are two isoforms of MSF; these are referred to as MSF+aa and MSF-aa, while the term MSF is used to include both.MSF was first identified as a motogen secreted by foetal and cancer-associated fibroblasts in tissue culture. It is also produced by sprouting (angiogenic) endothelial cells, tumour cells and activated macrophages. Keratinocytes and resting endothelial cells secrete inhibitors of MSF that have been identified as NGAL and IGFBP-7, respectively. MSF+aa and MSF-aa show distinct functionality in that only MSF+aa is inhibited by NGAL.MSF is present in 70-80% of all tumours examined, expressed by the tumour cells as well as by fibroblasts, endothelial cells and macrophages in the tumour microenvironment (TME). High MSF expression is associated with tumour progression and poor prognosis in all tumours examined, including breast carcinomas, non-small cell lung cancer (NSCLC), salivary gland tumours (SGT) and oral squamous cell carcinomas (OSCC). Epithelial and stromal MSF carry independent prognostic value. MSF is also expressed systemically in cancer patients, being detected in serum and produced by fibroblast from distal uninvolved skin. MSF-aa is the main isoform associated with cancer, whereas MSF+aa may be expressed by both normal and malignant tissues.The expression of MSF is not invariant; it may be switched on and off in a reversible manner, which requires precise interactions between soluble factors present in the TME and the extracellular matrix in contact with the cells. MSF expression in fibroblasts may be switched on by a transient exposure to several molecules, including TGFβ1 and MSF itself, indicating an auto-inductive capacity.Acting by both paracrine and autocrine mechanisms, MSF stimulates cell migration/invasion, induces angiogenesis and cell differentiation and alters the matrix and cellular composition of the TME. MSF is also a survival factor for sprouting endothelial cells. IGD tri- and tetra-peptides mimic the motogenic and angiogenic activities of MSF, with both molecules inhibiting AKT activity and requiring αvβ3 functionality. MSF is active at unprecedently low concentrations in a manner which is target cell specific. Thus, different bioactive motifs and extracellular matrix requirements apply to fibroblasts, endothelial cells and tumour cells. Unlike other motogenic and angiogenic factors, MSF does not affect cell proliferation but it stimulates tumour growth through its angiogenic effect and downstream mechanisms.The epithelial-stromal pattern of expression and range of bioactivities displayed puts MSF in the unique position of potentially promoting tumour progression from both the "seed" and the "soil" perspectives.

Tumor angiogenesis as an important prognostic factor in advanced non-small cell lung cancer (Stage IIIA)

The aim of the present study was to evaluate angiogenesis by determining the micro vascular density (MVD) and the expression of vascular endothelial growth factor (VEGF-A) in advanced non-small cell lung cancer (NSCLC) tumor samples, and to analyze their associations with clinical parameters and survival. Tumor tissue specimens of fifty patients (41 males and 9 females), who underwent radical surgical treatment for NSCLC in stage IIIA (T1-3N2) were collected for immunohistochemical analysis. MVD evaluation was performed using an anti-CD31 monoclonal antibody and VEGF-A expression using a polyclonal anti-VEGF-A antibody. The results were associated with two-year survival. Statistical analysis revealed significant associations in the level of angiogenesis (high MVD) and shorter survival of patients with NSCLC (P=0.0007). VEGF-A expression showed no association with micro vascular density (P=0.51) or survival (P=0.68). There was no significant association between MVD and VEGF-A. The measurable, clinical MVD parameters could be used as a reliable prognostic factor for the survival of patients with advanced NSCLC.

Microvascular proliferation is associated with aggressive tumour features and reduced survival in lung adenocarcinoma

Despite new treatment options in lung cancer, there is still a need for better biomarkers to assist in therapy decisions. Angiogenesis has been associated with tumour growth and dissemination, and the vascular proliferation index (VPI) is a valuable prognostic marker in other tumours. Nestin, a marker of immature endothelium, was previously applied in combination with Ki67 for proliferating endothelium as a novel marker (Nestin‐Ki67) of ongoing angiogenesis. Here, the prevalence and prognostic impact of vascular proliferation on lung cancer‐specific survival (LCSS) in lung adenocarcinomas was studied. Selected tumour slides from a cohort of 210 patients treated surgically for adenocarcinoma at Haukeland University Hospital (Norway) from 1993 to 2010 were stained for Nestin‐Ki67. VPI, the ratio between the density of proliferating vessels and the overall microvessel density were used, and the cut‐off value was set at 4.4% (upper quartile). High VPI was associated with the presence of blood vessel invasion (p = 0.007) and tumour necrosis (p = 0.007). Further, high VPI was significantly associated with reduced LCSS (p = 0.020). By multivariate analysis, VPI remained an independent prognostic factor for reduced LCSS (HR 1.7; 95% CI 1.04–2.68; p = 0.033) when adjusted for other prognostic clinico‐pathological features. In conclusion, microvessel proliferation assessed using the VPI was associated with aggressive tumour features such as blood vessel invasion and tumour necrosis and, independently, decreased LCSS. This marker should be further explored in separate cohorts, and in trials of anti‐angiogenesis therapy.

Child, neglect and oral health

Background

Despite advancements in oral health policies, dental caries still a problem. The lack of parents/caregiver’s care regarding child’s oral health, which characterizes neglect, may lead to a high prevalence of caries. Therefore, the objective of this study was to analyze the relation between dental caries and neglect in five year-old children.

Methods

Quantitative study performed in two different moments. First, the children underwent oral examinations and physical inspection. Then, a semi-structured interview was performed with parents of children with high and low caries rate.

Results

In all, 149 physical inspections and oral exams were performed. The number of decayed, missing and filled teeth – dmf-t was 2.75 (SD 2.83); 16 children had extremely high values (dmf-t ≥7), 85 intermediate values (1 ≤ dmf-t ≥ 6) and 48 extremely low (dmf-t = 0). Nearly all caregivers were female (96.7%; n = 29), mostly mothers (93.3%; n = 28). Associations were found between caries experience and reason of the last consultation (p = 0.011), decayed teeth and child’s oral health perception (p = 0.001). There was a trend towards a significant association between general health and decayed teeth (p = 0.079), general hygiene and caries experience (p = 0.083), and caries experience and number of times the child brushes the teeth (p = 0.086).

Conclusion

There’s a relation between caries experience and children’s oral health perception by caregivers, as well as between caries experience and children’s access to dental care. There is a trend towards association between caries experience and risk factors suggestive of neglect.

Opportunities and challenges in tumor angiogenesis research: back and forth between bench and bed

Angiogenesis is essential for tumor growth and metastasis. Many signaling pathways are involved in regulating tumor angiogenesis, with the vascular endothelial growth factor pathway being of particular interest. The recognition of the heterogeneity in tumor vasculature has led to better predictions of prognosis through differential analyses of the vasculature. However, the clinical benefits from antiangiogenic therapy are limited, because many antiangiogenic agents cannot provide long-term survival benefits, suggesting the development of drug resistance. Activation of the hypoxia and c-Met pathways, as well as other proangiogenic factors, has been shown to be responsible for such resistance. Vessel co-option could be another important mechanism. For future development, research to improve the efficacy of antiangiogenic therapy includes (a) using tumor-derived endothelial cells for drug screening; (b) developing the drugs focusing on specific tumor types; (c) developing a better preclinical model for drug study; (d) developing more accurate biomarkers for patient selection; (e) targeting the c-Met pathway or other pathways; and (f) optimizing the dose and schedule of antiangiogenic therapy. In summary, the future of antiangiogenic therapy for cancer patients depends on our efforts to develop the right drugs, select the right patients, and optimize the treatment conditions.

In vivo angiogenesis imaging of solid tumors by alpha(v)beta(3)-targeted, dual-modality micellar nanoprobes

The objective of this study was to develop and evaluate an alpha(v)beta(3)-specific nanoprobe consisting of fluorescent superparamagnetic polymeric micelles (FSPPM) for in vivo imaging of tumor angiogenesis. Spherical micelles were produced using poly(ethylene glycol)-b-poly(d,l-lactide) co-polymers conjugated with tetramethylrhodamine, a fluorescent dye, and loaded with superparamagnetic iron oxide nanoparticles. The resulting micelle diameter was 50-70 nm by dynamic light scattering and transmission electron microscopy measurements. Micelles were encoded with an alpha(v)beta(3)-specific peptide, cyclic RGDfK, and optimized for maximum fluorescence and targeting in alpha(v)beta(3)-overexpressing cells in vitro. In mice, cRGD-FSPPM-treated animals showed alpha(v)beta(3)-specific FSPPM accumulation in human lung cancer subcutaneous tumor xenografts. Together with the histological validation, the three-dimensional gradient echo magnetic resonance imaging (MRI) data provide high spatial resolution mapping and quantification of angiogenic vasculature in an animal tumor model using targeted, ultrasensitive MRI nanoprobes.

Assessment of vascularity as an index of angiogenesis in periradicular granulomas. Comparison with oral carcinomas and normal tissue counterparts

AIM

To quantify vascularity in periradicular granulomas using different endothelial markers, and assess its value as an index of angiogenesis by comparing granulomas with healthy periodontal ligament (PDL). To use oral tumours, compared with adjacent normal mucosa, as positive controls.

METHODOLOGY

Paraffin-embedded sections were stained with antibodies to von Willebrand factor (vWF), a pan-endothelial marker, and CD105, a putative marker for angiogenic vessels. Vascularity was quantified by different methods reflecting vessel volume and density.

RESULTS

Irrespective of the marker or method used, vascularity values were similar in periradicular granuloma and PDL. Both tissues were highly vascularized, with levels similar to those found in oral squamous cell carcinoma. Vascularity was significantly higher in the latter than in normal mucosa. Fewer vessels were positive for CD105 than for vWF in the normal mucosa, whereas similar numbers were found in the other tissues examined.

CONCLUSIONS

A comparison of vascularity in oral tumours and normal oral mucosa provided evidence of angiogenesis in the former. Staining with CD105 added limited value to staining with vWF in these tissues. In contrast, a comparison of periradicular granuloma and PDL failed to demonstrate evidence of angiogenesis in the granuloma. As all vessels were similarly stained with vWF and CD105 in granuloma and PDL, a possible hypothesis is that all vessels are newly formed in these tissues. A more plausible alternative is that CD105 expression may reflect the metabolic activity or intrinsic characteristics of the tissues, rather than the presence of angiogenic vessels.

Different growth patterns of non-small cell lung cancer represent distinct biologic subtypes

BACKGROUND

We have recently shown the prognostic value of growth pattern classification in non-small cell lung cancer. The aim of this study is to validate the hypothesis that these growth patterns have a distinct angiogenic and proliferative profile.

METHODS

Hematoxylin-eosin stained tissue sections of 239 patients with non-small cell lung cancer were classified into growth patterns. One representative tissue section per patient was double immunostained with CD34 and Ki-67 antibodies. Endothelial cell proliferation fraction, tumor cell proliferation fraction, microvessel density, and Chalkley count were assessed at the invading front and the center of the selected tumor section.

RESULTS

According to the growth pattern classification, 161 patients (67.4%) had a destructive, 33 (13.8%) a papillary, and 45 (18.8%) an alveolar growth pattern. There were significant differences in endothelial cell proliferation fraction (p < 0.001), tumor cell proliferation fraction (p < 0.001), microvessel density (p < 0.001), and Chalkley count (p < 0.001) between the growth patterns. Multiple Cox regression analysis showed that a low endothelial cell proliferation fraction was consistently an independent prognostic factor for overall poor (hazard ratio = 0.93; confidence interval: 0.88 to 0.97, p = 0.002) and disease-free survival (hazard ratio = 0.94; confidence interval: 0.89 to 0.98, p = 0.007).

CONCLUSIONS

Growth patterns have a distinct angiogenic and proliferative profile. In non-small cell lung cancer, a low degree of angiogenesis (a low endothelial cell proliferation fraction) is associated with poor prognosis.

The Significance and Relationship between Mast Cells and Tumour Angiogenesis in Non-small Cell Lung Carcinoma

This study investigated whether microvessel density (MVD) and mast cell infiltration are related to prognosis in non-small cell lung carcinoma (NSCLC), and examined the possible role of mast cells in NSCLC angiogenesis. MVD and mast cell infiltration were analysed retrospectively in tumour specimens from 50 patients with primary NSCLC. Immunohistochemistry with monoclonal antibody anti-CD34 was used to delineate the microvessels and routine Giemsa blue staining was used to assess the number of mast cells. Significant correlations were found between MVD and mast cell infiltration and between MVD and both lymph node metastasis and tumour, node, metastases (TNM) stage. No significant correlations were found with respect to survival for MVD or mast cell infiltration. Multivariate analysis showed that TNM stage and tumour size were independent predictors of survival, suggesting that the TNM staging system remains the most important tool for the estimation of prognosis in NSCLC patients.

Fluorodeoxyglucose uptake of primary non-small cell lung cancer at positron emission tomography: new contrary data on prognostic role

PURPOSE

This prospective study evaluated the prognostic significance of (18)F-fluorodeoxyglucose ((18)F-FDG) uptake in primary non-small cell lung cancer (NSCLC) at positron emission tomography, in a carefully staged population, while correcting for partial volume effects.

EXPERIMENTAL DESIGN

Two hundred eight potentially resectable NSCLC patients were referred for FDG positron emission tomography staging after thoracic computed tomography. Each tumor stage was confirmed surgically, or for some stage IV tumors by additional imaging. The tumor maximum pixel-standardized uptake value (maxSUV) and the maxSUV partial volume corrected for lesion size (PVCmaxSUV) were compared with overall survival and disease-free survival using Cox proportional hazards regression.

RESULTS

Stage distribution: stage I, 36%; stage II, 15%; stage III, 30%; stage IV, 19%. Patients were followed for a median of 33.6 months, with 90 deaths from NSCLC (median survival for all stages, 43.3 months). With respect to overall survival, the most significant cutoff value for both maxSUV and PVCmaxSUV was 7. MaxSUV > or =7 was significantly associated with an increased risk of death from NSCLC in univariable analysis, whereas PVCmaxSUV > or =7 was only marginally associated. However, in multivariable analyses, neither maxSUV > or =7 nor PVCmaxSUV > or =7 provided significant additional prognostic information over stage, tumor size, and age. In the 103 patients who underwent surgical resection only, surgical stage, but not maxSUV or PVCmaxSUV, was univariably associated with survival or recurrence. SUV definitions based on lean body mass, body surface area, and plasma glucose correction yielded identical results.

CONCLUSIONS

As expected, tumor stage is prognostic in NSCLC. However, tumor FDG uptake does not provide additional prognostic information. This prospective study contradicts prior reports.

Microvessel density as a prognostic factor in non-small-cell lung carcinoma: a meta-analysis of individual patient data

BACKGROUND

Angiogenesis is a potential prognostic factor that has been investigated in patients with non-small-cell lung carcinoma. However, published studies of the role of angiogenesis as a prognostic factor are inconclusive. We aimed to collect individual patient data to assess microvessel-density counts (ie, a measure of angiogenesis) as a prognostic factor in non-small-cell lung carcinoma.

METHODS

We obtained published and unpublished datasets and extracted appropriate data, taking particular care to ensure data quality. Detailed information was obtained for the laboratory methods used by every research centre that generated the data. The outcome of interest was overall survival. We did a meta-analysis to estimate the prognostic role of microvessel density by combining separately estimated hazard ratios (HR) from every study, which were adjusted for tumour stage and age. Analyses were done separately for studies that used the Chalkley method or for those that counted all microvessels.

FINDINGS

17 centres provided data for 3200 patients, 2719 of which were included in the analysis. All but three centres (datasets 9, 10, and 13-367 cases) had already published their findings, and six had updated follow-up information (datasets 1, 2, 3, 6, 7, and 8-1273 cases). For all but three centres (datasets 4, 11, and 13) some data corrections were necessary. For microvessel density counts obtained by the Chalkley method, the HR for death per extra microvessel was 1.05 (95% CI 1.01-1.09, p=0.03) when analysed as a continuous variable. For microvessel density counts obtained by the all vessels method, the HR for death per ten extra microvessels was 1.03 (0.97-1.09, p=0.3) when analysed as a continuous variable.

INTERPRETATION

Microvessel density does not seem to be a prognostic factor in patients with non-metastatic surgically treated non-small-cell lung carcinoma. This conclusion contradicts the results of a meta-analysis of published data only. Therefore, the methodology used to assess prognostic factors should be assessed carefully.

Identification and clinical significance of circulating endothelial progenitor cells in human non-small cell lung cancer

Until recently, it was generally accepted that vascularization of tumors arises exclusively from endothelial sprouting. Whether circulating bone marrow-derived endothelial progenitor cells (EPC) participate in the progression of non-small cell lung cancer (NSCLC) has not yet been evaluated. EPCs labeled with CD34, CD133, and vascular endothelial growth factor receptor-2 (VEGFR2) antibodies were counted by flow cytometry in the peripheral blood of 53 NSCLC patients. Furthermore, by means of a quantitative reverse transcription-PCR approach, we measured VEGFR2, CD133, CD34, and VE-cadherin mRNA in the peripheral blood samples of the same patient population. EPCs in tumor samples were identified by confocal microscopy using CD31, CD34, CD133, and VEGFR2 antibodies. Although immunofluorescent labeling of microvessels made clear that incorporation of EPCs is a rare phenomenon in NSCLC tissue (9 of 22 cases), circulating EPC levels before therapeutic intervention were increased in NSCLC patients (P < 0.002, versus healthy controls), and high pretreatment circulating EPC numbers correlated with poor overall survival (P < 0.001). Furthermore, in the subgroup of responders to treatment, the posttreatment EPC numbers in the peripheral blood were significantly lower compared with nonresponding patients. Interestingly, pretreatment mRNA levels of CD133, VE-cadherin, and CD34 were not significantly increased in NSCLC patients, whereas VEGFR2 expression was increased by 80-fold. Moreover, posttreatment VEGFR2 mRNA level in the peripheral blood was significantly higher in the subgroup of nonresponding patients when compared with posttreatment level of patients responding to antitumor therapy. Circulating levels of bone marrow-derived EPCs are significantly increased in NSCLC patients and correlate with clinical behavior.

Evidence for a field change effect based on angiogenesis in the oral mucosa? A brief report

The concept of field cancerisation was proposed to explain the development of second primary tumours in the upper aerodigestive tract. The formation of new blood vessels (angiogenesis) has been shown to accompany oral disease progression, however, little is known about its potential role as an indicator of field cancerisation. The aims of this study were to compare the angiogenic profile of normal oral mucosa from oral cancer patients with that sampled from cancer-free patients to seek evidence for differences that might be termed a field change. Oral mucosal tissue (NC) was obtained from 25 oral cancer patients from a site at least 1 cm distant from the primary tumour and was compared with normal oral mucosa (NN) from a further 20 non-cancer patients. The vascularity of the tissue was investigated immunohistochemically using four antibodies and three methods of quantitation. Vascularity was significantly higher in the NC group than the NN with all four markers (p<0.01). Significantly higher indices of vascularity were found for patients who were smoker/drinkers in the NC group (p<0.05). The increased vascularity may provide a rationale for anti-angiogenic drug therapy for tertiary prevention.

A Three-dimensional Analysis of Blood Vessels in Bronchioloalveolar Carcinoma

The three-dimensional architecture of blood vessels within lung adenocarcinomas has not been well studied. In 19 cases with bronchioloalveolar carcinoma with central fibrosis, we three-dimensionally examined blood vessel architecture in 150 microm thick sections stained with elastin staining and anti-CD34 antibody. We examined four regions: normal alveoli and three regions within the tumor including an area adjacent to the normal alveoli (external area), an area in which tumor cells were replacing epithelial cells (replacement area), and a central fibrotic area (fibrotic area). Elastin staining showed that elastic fibers formed the framework of the alveoli, and the alveolar structure shrank more strongly to the center of the tumor due to folding of alveolar walls invaded by adenocarcinoma cells. We also measured three vessel parameters in these four regions. The vessel diameters were 4.08+/-1.10 microm, 3.95+/-1.02 microm, 5.04+/-1.56 microm, and 6.11+/-2.23 microm, the circumferences of those vessels seen as complete circles were 43.11+/-12.78 microm, 43.71+/-12.87 microm, 95.21+/-39.32 microm, and 126.77+/-54.65 microm; the lengths between vessel bifurcations were 13.28+/-3.08 microm, 13.47+/-4.58 microm, 24.91+/-9.66 microm, and 41.82+/-28.08 microm in the normal alveoli, and the external, replacement, and fibrotic areas, respectively. Blood vessel architecture changed such that the vessels became larger and coarser towards the center of the tumor. Our three-dimensional analysis suggests continuous remodeling of alveolar capillaries rather than angiogenesis within bronchioloalveolar carcinoma.

Prognostic value of nonangiogenic and angiogenic growth patterns in non-small-cell lung cancer

An essential prerequisite of nonangiogenic growth appears to be the ability of the tumour to preserve the parenchymal structures of the host tissue. This morphological feature is visible on a routine tissue section. Based on this feature, we classified haematoxylin and eosin-stained tissue sections from 279 patients with non-small-cell lung cancer into three growth patterns: destructive (angiogenic; n=196), papillary (intermediate; n=38) and alveolar (nonangiogenic; n=45). A Cox multiple regression model was used to test the prognostic value of growth patterns together with other relevant clinicopathological factors. For overall survival, growth pattern (P=0.007), N-status (P=0.001), age (P=0.020) and type of operation (P=0.056) were independent prognostic factors. For disease-free survival, only growth pattern (P=0.007) and N-status (P<0.001) had an independent prognostic value. Alveolar (hazard ratio=1.825, 95% confidence interval=1.117–2.980, P=0.016) and papillary (hazard ratio=1.977, 95% confidence interval=1.169–3.345, P=0.011) growth patterns were independent predictors of poor prognosis. The proposed classification has an independent prognostic value for overall survival as well as for disease-free survival, providing a possible explanation for survival differences of patients in the same disease stage.

Upregulation of the tissue inhibitor of metalloproteinase-1 protein is associated with progression of human non-small-cell lung cancer

PURPOSE

Tissue inhibitors of metalloproteinases (TIMPs) are naturally occurring inhibitors of matrix metalloproteinases (MMPs). It has been shown that TIMP-1 may be a multifunctional protein. Little is known about the role of TIMP-1 in progression and metastasis of human lung cancer (tumor inhibiting or tumor promoting), although studies using a variety of techniques have analyzed the expression of TIMP-1 mRNA and/or protein in human cancers.

PATIENTS AND METHODS

We examined the expression of TIMP-1 protein by immunohistochemistry in patients (n = 160) with primary respectable (stage I to IIIA) non-small-cell lung cancer (NSCLC).

RESULTS

Twenty-seven percent of the tumors (43 of 160) demonstrated elevated expression of this protein. We demonstrate that overexpression of TIMP-1 protein is associated with an adverse outcome. In addition, disease stage, patient's age, and performance status were all significantly related to survival. In multivariate analyses, patients with high TIMP-1 expression had a 90% increased risk of death when compared with those with low expression (relative risk, 1.92; 95% CI, 1.19 to 3.09; P =.008). TIMP-1 expression did not correlate with expression of MMP-2 and MMP-9.

CONCLUSION

These results suggest that TIMP-1, independent of its inhibiting activity of MMPs, may have other function(s) critical for NSCLCs. The significance of our results is two-fold. The adverse outcome in patients with overexpression of TIMP-1 indicates its potential prognostic value in NSCLC. Thus, TIMP-1 overexpression may serve to help identify patients with particularly aggressive disease for adjuvant treatments. In addition, the TIMP-1 molecule may represent a novel therapeutic target for treatment of some NSCLCs.

Prognostic implications of neuroendocrine differentiation and hormone production in patients with Stage I nonsmall cell lung carcinoma

BACKGROUND

Approximately 10-20% of nonsmall cell lung carcinomas (NSCLC) show neuroendocrine (NE) differentiation, as evaluated by panendocrine markers or ultrastructural evidence of dense-core secretory granules. However, little is known regarding the prevalence and clinical implications of NE differentiation in patients with Stage I NSCLC.

METHODS

The authors analyzed 220 consecutive patients with Stage I NSCLC (pT1-T2N0M0) among 2100 patients with primary lung carcinoma who underwent surgical treatment between 1987 and 1993. Using light microscopy and immunohistochemical staining for synaptophysin, chromogranin A, and respiratory tract-related hormones, 28 NSCLC specimens with NE differentiation (NSCLC-ND) and 11 large cell neuroendocrine carcinoma (LCNEC) specimens were identified.

RESULTS

The 28 NSCLC-ND specimens included 15 adenocarcinomas and 13 squamous cell carcinomas. Neoplastic cells with NE features never exceeded 20% in NSCLC-ND specimens, whereas neoplastic cells amounted to 20-90% in LCNEC specimens. NSCLC-ND specimens with > 5% NE-differentiated tumor cells showed increased Ki-67 labeling index (P = 0.007) and invasive phenotype, as evaluated by fascin immunoreactivity (P = 0.021). Patients with adenocarcinoma, but not with squamous cell carcinoma, who had > 5% NE-differentiated cells had a worse clinical course compared with patients who had ordinary NSCLC, with reduced overall survival (P = 0.017) and disease free survival (P = 0.049). In multivariate analysis, NE differentiation > 5% neoplastic cells in patients with adenocarcinoma independently predicted a poorer prognosis (hazard ratio, 2.61; 95% confidence interval, 0.99-6.85). Hormone production was restricted to chromogranin positive NSCLC-ND but did not affect prognosis.

CONCLUSIONS

Stage I adenocarcinomas with >or= 5% NE tumor cells are clinically aggressive tumors, similar to LCNEC. Hormone production identifies a more fully developed neuroendocrine phenotype but is not relevant to prognosis. The identification of NE-differentiated cells in patients with NSCLC may have clinical relevance.

Correlation between apoptotic index and angiogenesis in non-small cell lung cancer: comparison between CD105 and CD34 as a marker of angiogenesis

Only a few clinical studies have documented a significant correlation between intratumoral microvessel density (IMVD), a measurement of angiogenesis, and apoptotic index (AI), an incidence of apoptosis, although many experimental studies have confirmed that insufficient angiogenesis induces accelerated apoptotic cell death. In the present study, therefore, to assess AI in correlation with IMVD in resected non-small cell lung cancer, a total of 236 patients with pathologic stage I to IIIa were reviewed. IMVDs were determined immunohistochemically with an antibody against a pan-endothelial marker, CD34 (CD34-IMVD), and an antibody against a proliferation-related endothelial marker, CD105 (CD105-IMVD). AI was defined as the number of tumor cells positive for the terminal deoxynucleotidyl tranferase-mediated dUTP-biotin nick end-labeling staining per 1000 tumor cells. When CD34 was used as a marker of angiogenesis, the mean AIs for the lower-IMVD and the higher-IMVD patients were 20.1 and 17.5, respectively, demonstrating no significant difference between the lower- and the higher-IMVD patients. In contrast, when CD105 was used, the mean AI for the lower-IMVD patients was significantly higher than that for the higher-IMVD patients (22.0 and 15.6, respectively; P=0.019). There was no significant correlation between proliferative activity and CD34-IMVD or CD105-IMVD. These results demonstrated that that decreased angiogenesis may induce enhanced apoptotic tumor-cell death without affecting cell proliferation.

The role of microvessel density on the survival of patients with lung cancer: a systematic review of the literature with meta-analysis

In order to determine whether angiogenesis is a prognostic marker in lung cancer, we performed a systematic review of the literature to assess the prognostic value on survival of microvessel count in patients with lung cancer. Published studies were identified by an electronic search in order to aggregate survival results, after a methodological assessment using a quality scale designed by the European Lung Cancer Working Party. To be eligible, a study had to deal with microvessel count assessment in lung cancer patients on the primary site and to provide survival analysis according to microvessel count expression. Microvessel count has been assessed on surgical samples by immunohistochemistry using factor VIII in 14 studies, CD34 in 10 and CD31 in eight. Respectively 1866, 1440 and 1093 non-small cell lung cancer patients were considered. The overall median quality scores were respectively 52, 59 and 59% for studies assessing microvessel count via factor VIII, CD34 and CD31, without significant difference between studies evaluable or not for meta-analysis nor between studies with significant or non significant results. Seven 'factor VIII' studies, nine 'CD34' and seven 'CD31' provided sufficient data allowing a meta-analysis on survival and were evaluable for results aggregation. This showed that a high microvessel count in the primitive lung tumour was a statistically significant poor prognostic factor for survival in non small cell lung cancer whatever it was assessed by factor VIII (HR: 1.81; 95% CI: 1.16-2.84), CD34 (HR: 1.99; 95% CI: 1.53-2.58) or CD31 (HR: 1.80; 95% CI: 1.10-2.96). Variations in survival among the individual studies can be explained in addition to patients selection criteria by the heterogeneous methodologies used to stain and count microvessels: different antibody clones, identification of 'hotspots', Weidner or Chalkey counting method, cut-off selection. Microvessel count, reflecting the angiogenesis, appears to be a poor prognostic factor for survival in surgically treated non small cell lung cancer but standardisation of angiogenesis assessment by the microvessel count is necessary.

Prognostic factors in non-small cell lung cancer: a decade of progress

STUDY OBJECTIVES

To provide a systematic overview of the literature investigating patient and tumor factors that are predictive of survival for patients with non-small cell lung cancer (NSCLC), and to analyze patterns in the design of these studies in order to highlight problematic aspects of their design and to advocate for appropriate directions of future studies.

DESIGN

A systematic search of the MEDLINE database and a synthesis of the identified literature.

MEASUREMENTS AND RESULTS

The database search (January 1990 to July 2001) was carried out combining the MeSH terms prognosis and carcinoma, nonsmall cell lung. Eight hundred eighty-seven articles met the search criteria. These studies identified 169 prognostic factors relating either to the tumor or the host. One hundred seventy-six studies reported multivariate analyses. Concerning 153 studies reporting a multivariate analysis of prognostic factors in patients with early-stage NSCLC, the median number of patients enrolled per study was 120 (range, 31 to 1,281 patients). The median number of factors reported to be significant in univariate analyses was 4 (range, 2 to 14 factors). The median number of factors reported to be significant in multivariate analyses per study was 2 (range, 0 to 6 factors). The median number of studies examining each prognostic factor was 1 (range, 1 to 105 studies). Only 6% of studies addressed clinical outcomes other than patient survival.

CONCLUSIONS

While the breadth of prognostic factors studied in the literature is extensive, the scope of factors evaluated in individual studies is inappropriately narrow. Individual studies are typically statistically underpowered and are remarkably heterogeneous with regard to their conclusions. Larger studies with clinically relevant modeling are required to address the usefulness of newly available prognostic factors in defining the management of patients with NSCLC.

Flow cytometric quantification of tumour endothelial cells; an objective alternative for microvessel density assessment

Assessment of microvessel density by immunohistochemical staining is subject to a considerable inter-observer variation, and this has led to variability in correlation between microvessel density and clinical outcome in different studies. In order to improve the method of microvessel density measurement in tumour biopsies, we have developed a rapid, objective and quantitative method using flow cytometry on frozen tissues. Frozen tissue sections of archival tumour material were enzymatically digested. The single-cell suspension was stained for CD31 and CD34 for flow cytometry. The number of endothelial cells was quantified using light scatter- and fluorescence-characteristics. Tumour endothelial cells were detectable in a single cell suspension, and the percentage of endothelial cells detected in 32 colon carcinomas correlated highly (r=0.84, P<0.001) with the immunohistochemical assessment of microvessel density. Flow cytometric endothelial cells quantification was found to be more sensitive especially at lower levels of immunohistochemical microvessel density measurement. The current method was found to be applicable for various tumour types and has the major advantage that it provides a retrospective and quantitative approach to the angiogenic potential of tumours.

Quantitative evaluation of angiogenesis in laryngeal cancer by digital image measurement of the vessel density

OBJECTIVE

the aim of our study was determination of the relationship between angiogenesis and clinical as well as histological features in laryngeal cancer.

METHODS

we used two different methods of estimation of the amount of microvessels in the series of 55 cases, e.g. classical count of endothelial cells group (h-MVD) and digital image measurement of the vessel density (VD).

RESULTS

neither h-MVD nor VD correlated significantly with clinical features of the tumour. The results of VD examination correlated significantly with the existence of nodal metastases (P=0.02). The relationship between h-MVD and N status was on the statistical borderline (P=0.07). Multivariate analysis of Cox's proportional hazards model revealed that only N status correlated significantly with patients' survival.

CONCLUSION

our results indicate that measurements of angiogenesis in laryngeal cancer may be of some value in predicting N status in laryngeal cancer patients. This issue should be confirmed in prospective studies.

Elevated preoperative serum levels of angiogenic cytokines correlate to larger primary tumours and poorer survival in non-small cell lung cancer patients

We have analysed the predictive and prognostic information in preoperatively collected serum levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in patients clinically evaluated as operable non-small cell lung cancer (NSCLC). Fifty-eight patients with operable NSCLC were included. VEGF and bFGF levels in serum were analysed using enzyme linked immunosorbent assays (Quantikine human VEGF and Quantikine HS human FGF basic, R&D Systems). Univariate analysis demonstrated that tumour volume, platelet counts, VEGF and bFGF were significant prognostic factors. However, only bFGF remained significant in the multivariate analysis (P=0.014). Significant correlation's were demonstrated between VEGF levels and tumour volume (r=0.33; P=0.012) and platelet count (r=0.43; P=0.001). bFGF levels correlated significant with recurrent disease (r=0.34; P=0.01), platelet count (r=0.53, P<0.001) and performance status (r=0.29; P=0.029). Furthermore, bFGF levels and VEGF levels correlated significantly (r=0.44; P<0.001). We conclude that elevated circulating angiogenic cytokines correlate with tumour volume, higher relapse risk and poorer survival in patients with operable non-small cell lung cancer.

Immunoreactivity for thyroid transcription factor-1 in stage I non-small cell carcinomas of the lung

Thyroid transcription factor-1 (TTF-1) is a nuclear protein regulating the transcriptional activity of lung-specific genes in the normal and neoplastic bronchioloalveolar cells. It has been implicated in the normal growth and development of the lung, and the disruption of the TTF-1 locus leads to neonatal death with pulmonary hypoplasia. We evaluated retrospectively the prevalence and clinical significance of TTF-1 immunoreactivity in 222 patients with stage I non-small cell lung carcinoma (NSCLC) with a follow-up time of at least 5 years, and we investigated its relationship with other markers of tumor growth, namely cell proliferation and angiogenesis. TTF-1 immunoreactivity was documented by using the commercially available monoclonal antibody 8G7G3/1 in 72% of 97 adenocarcinomas, 5% of 119 squamous cell carcinomas, and in the glandular component of two adenosquamous carcinomas. Four large cell carcinomas were completely unreactive. In adenocarcinomas, but not squamous cell carcinomas, TTF-1 immunoreactivity correlated significantly with microvessel density (p = 0.04) and inversely with the tumor proliferation fraction assessed by Ki-67 immunostaining (p = 0.03). Also, TTF-1-immunoreactive adenocarcinomas showed a trend for a size less than 3 cm (p = 0.08). TTF-1 expression was not related to specific growth patterns, tumor grade, or tumor cell typing. TTF-1 immunoreactivity did not significantly affect patient survival, although patients with more than 75% immunoreactive neoplastic cells showed a trend for longer overall and disease-free survival. Our findings suggest that TTF-1 could be involved in the development of small pulmonary adenocarcinomas, but it has not prognostic implications in patients with stage I NSCLC.

Prognostic value of vascularity and vascular endothelial growth factor expression in non-small cell lung cancer

AIMS

High expression of the angiogenic factor vascular endothelial growth factor (VEGF) in tumours has been found to be associated with poor prognosis in some studies, but not in others. The aims of this study were to determine the prognostic value of VEGF in operable non-small cell lung cancer (NSCLC) and its possible association with vascularity.

METHODS

Sections from 81 NSCLC archival specimens were stained with antibodies to von Willebrand factor (vWF) and VEGF. Vascularity was measured by the average density of vWF positive vessels. VEGF expression in tumour cells was assessed by consensus of two independent observers according to three indices, namely: (1) percentage of area stained, (2) intensity of staining, and (3) final score (product of area and intensity).

RESULTS

VEGF immunoreactivity was present in all tumours and adjacent normal lung tissue. None of the three VEGF indices was associated with vascularity or the clinical parameters examined. Mean survival times were shorter in patients with high VEGF expression, but the difference was not significant. This applied to the full cohort of patients, or when analysed separately according to tumour type or stage. However, high VEGF expression was associated with poor survival in patients with high vascularity (p = 0.02). VEGF had no discriminant value among patients with low vascularity. Vascularity had no prognostic value, except for late stage patients (UICC stages II and IIIa combined; n = 36), where high vascularity was associated with longer survival (p = 0.01).

CONCLUSIONS

VEGF on its own has no prognostic value in NSCLC, but may become a useful indicator when combined with vascularity. VEGF may play a physiological role in the normal lung.

Prognostic significance of platelet and microvessel counts in operable non-small cell lung cancer

BACKGROUND

Microvessel density, an indirect measure of angiogenesis, has been shown to be an independent prognostic marker in many solid tumours including non-small cell lung cancer (NSCLC). Platelets transport and release angiogenic growth factors. Platelets are increasingly likely to adhere to tumour microvessels due to raised expression of platelet-binding proteins and stasis in blood-flow. Increased vascular permeability in tumour microvessels facilitates platelet extravasation into the extracellular matrix. Adherence and extravasation both lead to platelet activation and release of growth factors capable of instigating the angiogenic process.

METHODS

A total of 181 patients were identified who underwent resection of stage I-IIIa NSCLC with a post-operative survival >60 days. Patients were followed-up for a minimum of 24 months. Sections from the tumour periphery were stained for the endothelial marker CD34 (Novocastra NCL-END) using standard ABC immunohistochemistry. Chalkley counting was used to assess microvessel density.

RESULTS

A pre-operative platelet count greater than the median and above the normal range (>400) was associated with a poor outcome (P=0.01 and P=0.04, respectively). Tumours with an above median and high Chalkley count (upper tertile) had a worse prognosis (P=0.007 and P=0.0006, respectively). There was no association between platelet count and Chalkley count.

CONCLUSIONS

Platelet and microvessel counts are both potential prognostic markers for NSCLC. The role of platelets in the angiogenic process needs to be further investigated.

Molecular biology of breast cancer metastasis. Molecular expression of vascular markers by aggressive breast cancer cells

During embryogenesis, the formation of primary vascular networks occurs via the processes of vasculogenesis and angiogenesis. In uveal melanoma, vasculogenic mimicry describes the 'embryonic-like' ability of aggressive, but not nonaggressive, tumor cells to form networks surrounding spheroids of tumor cells in three-dimensional culture; these recapitulate the patterned networks seen in patients' aggressive tumors and correlates with poor prognosis. The molecular profile of these aggressive tumor cells suggests that they have a deregulated genotype, capable of expressing vascular phenotypes. Similarly, the embryonic-like phenotype expressed by the aggressive human breast cancer cells is associated with their ability to express a variety of vascular markers. These studies may offer new insights for consideration in breast cancer diagnosis and therapeutic intervention strategies.

Vascular endothelial growth factor, platelet-derived endothelial cell growth factor and angiogenesis in non-small-cell lung cancer

High microvessel density, an indirect measure of angiogenesis, has been shown to correlate with increased tumour size, lymph node involvement and poor prognosis in non-small-cell lung cancer (NSCLC). Tumour cell vascular endothelial growth factor (VEGF) and platelet-derived endothelial cell growth factor (PD-ECGF) expression correlate with angiogenesis and a poor outcome in this disease. In a retrospective study VEGF and PD-ECGF expression and microvessel density were evaluated immunohistochemically in surgically resected specimens (T1-3, N0-2) from 223 patients with operable NSCLC using the VG1, P-GF.44C and JC70 monoclonal antibodies respectively. High VEGF immunoreactivity was seen in 104 (46.6%) and PD-ECGF in 72 (32.3%) cases and both were associated with high vascular grade tumours (P= 0.009 and P= 0.05 respectively). Linear regression analysis revealed a weak positive correlation between VEGF and PD-ECGF expression in cancer cells (r= 0.21; P = 0.002). Co-expression of VEGF and PD-ECGF was not associated with a higher microvessel density than VEGF or PD-ECGF only expressing tumours. Furthermore a proportion of high vascular grade tumours expressed neither growth factor. Univariate analysis revealed tumour size, nodal status, microvessel density and VEGF and PD-ECGF expression as significant prognostic factors. Tumour size (P < 0.02) and microvessel density (P < 0.04) remained significant on multivariate analysis. In conclusion, VEGF and PD-ECGF are important angiogenic growth factors and have prognostic significance in NSCLC. Furthermore the study underlines the prognostic significance of microvessel density in operable NSCLC.

Vascular endothelial growth factor expression and neovascularisation in non-small cell lung cancer

Many recent studies have demonstrated that tumour angiogenesis is a potent prognostic factor for various malignant tumours, but this has not been clearly shown in non-small cell lung carcinoma (NSCLC). The purpose of this study was to re-evaluate the prognostic value of MVD associated with VEGF in patients with NSCLC by comparing the immunohistochemical results obtained for CD34 with those obtained for vWf. Microvessel density (MVD) and the expression of vascular endothelial growth factor (VEGF) were investigated in 108 cases of NSCLC by immunohistochemistry. The correlation between von Willebrand factor (vWf) and CD34 staining for MVD was not strong, and vWf staining did not correlate with VEGF expression, but CD34 staining did. Staining for CD34 significantly correlated with survival in adenocarcinoma, distant metastasis and postoperative recurrence, but staining for vWf did not. CD34 was more sensitive and specific than vWf for staining endothelial cells associated with VEGF expression. It is suggested that research on neovascularisation should be investigated on every histological subtype or should focus on the early stages of NSCLC which are not under the influence of a variety of complications facilitating tumour neovascularisation.

Vasculogenic mimicry and tumor angiogenesis

Tumors require a blood supply for growth and hematogenous dissemination. Much attention has been focused on the role of angiogenesis-the recruitment of new vessels into a tumor from pre-existing vessels. However, angiogenesis may not be the only mechanism by which tumors acquire a microcirculation. Highly aggressive and metastatic melanoma cells are capable of forming highly patterned vascular channels in vitro that are composed of a basement membrane that stains positive with the periodic acid-Schiff (PAS) reagent in the absence of endothelial cells and fibroblasts. These channels formed in vitro are identical morphologically to PAS-positive channels in histological preparations from highly aggressive primary uveal melanomas, in the vertical growth phase of cutaneous melanomas, and in metastatic uveal and cutaneous melanoma. The generation of microvascular channels by genetically deregulated, aggressive tumor cells was termed "vasculogenic mimicry" to emphasize their de novo generation without participation by endothelial cells and independent of angiogenesis. Techniques designed to identify the tumor microcirculation by the staining of endothelial cells may not be applicable to tumors that express vasculogenic mimicry. Although it is not known if therapeutic strategies targeting endothelial cells will be effective in tumors whose blood supply is formed by tumor cells in the absence of angiogenesis, the biomechanical and molecular events that regulate vasculogenic mimicry provide opportunities for the development of novel forms of tumor-targeted treatments. The unique patterning characteristic of vasculogenic mimicry provides an opportunity to design noninvasive imaging techniques to detect highly aggressive neoplasms and their metastases.

Molecular pathogenesis of lung cancer

Lung cancer is the largest cancer killer of men and women in the united states. In addition to the progress made from antismoking primary prevention measures, new tools to help treat patients with lung cancer are emerging from the rapid advances in knowledge of the molecular pathogenesis of lung cancer. These tools include molecular and cellular biology and are starting to provide an insight into how the tumor cell, by altering oncogenes and tumor suppressor genes, achieves growth advantage, uncontrolled proliferation and metastatic behavior via disruption of key cell-cycle regulators and signal transduction cascades. Moreover, new knowledge is being developed in terms of the molecular definition of individual susceptibility to tobacco smoke carcinogens. These tools are being translated into clinical strategies to complement surgery, radiotherapy, and chemotherapy and also to assist in primary and secondary prevention efforts. This review summarizes current knowledge of the molecular pathogenesis of lung cancer. From this we know that respiratory epithelial cells require many genetic alterations to become invasive and metastatic cancer. We can detect cells with a few such changes in current and former smokers, offering the opportunity to intercede with a biomarker-monitored prevention and early detection effort. This will be coupled with new advances in computed tomography-based screening. Finally, because the molecular alterations are known, new mechanism-based therapies are being developed and brought to the clinic, including new drugs, vaccines, and gene therapy, which also must be integrated with standard therapies.

Tumor angiogenesis and recurrence in stage I non-small cell lung cancer

BACKGROUND

Tumor angiogenesis appears to relate to recurrence after an operation as a route for distant metastasis. We assessed the association of vascular endothelial growth factor (VEGF) expression and intratumoral microvessel density (MD) with recurrence in primary lung cancer.

METHODS

Samples were randomly obtained from 104 stage I lung cancer patients who underwent curative operations (43 recurrent, 61 nonrecurrent patients). Microvessels were highlighted by staining endothelial cells for factor VIII and VEGF antigen was detected using a polyclonal antibody.

RESULTS

VEGF antigen was detected in large amounts in both recurrent (100%) and nonrecurrent tumors (73.8%). The percentages of patients with the strongest VEGF stain (more than 50% of staining area in tumor cells) were 46.5% in tumors with recurrence and 11.5% in tumors without recurrence. The mean MD in recurrent and nonrecurrent tumors were 18.2+/-10.5 and 8.5+/-5.0, respectively, resulting in a significantly greater value in tumors with recurrence (p<0.0001). Although there were no significant differences in mean MD according to pathological types, in adenocarcinoma and adenosquamous carcinoma, the mean value in the recurrent group was significantly greater than that in the nonrecurrent one.

CONCLUSIONS

An evaluation of VEGF expression and MD in tumors may contribute to the estimation of the risk of recurrence of non-small cell lung cancer in early stages.

Assessment of vascularity in histological sections: effects of methodology and value as an index of angiogenesis in breast tumours

The aims of this study were to (a) determine how the quantification of blood vessels in histological sections (vascularity) is affected by the methodology used and (b) assess the value of vascularity as an index of angiogenesis by comparing tumour and normal breast tissue. Archival specimens of breast, lung and oral carcinoma, oral dysplasia and normal breast tissue were used to test the effects of the following experimental variables on vascularity: pretreatment of the sections (enzymatic digestion, heating), endothelial markers (von Willebrand factor and CD31 antibodies), method of quantification (highest microvascular density, average microvascular density and microvascular volume) and interobserver variations. All the variables examined significantly affected the estimated vascularity; this depended on the type of tissue and method used. The pretreatment of the sections before staining was the most important variable, altering the vascularity ranking of the tumours. Vascularity in breast tumours was similar to that of the normal breast intralobular stroma, suggesting that an area of high microvascular density in the tumour does not necessarily represent tumour-induced angiogenesis. Contradictory results have been published regarding the value of vascularity as a tumour prognostic factor. Our results suggest that statistically significant differences in vascularity values are most likely to arise from failure to optimize the staining protocol and from the method used to assess vascularity.

Heterogeneity in microvascular density in lung tumours: comparison with normal bronchus

The aim of this study was to test the hypotheses that (a) microvascular density (MVD) measured in histological sections of resected non-small cell lung carcinomas is an index of angiogenesis and (b) the measurement of MVD in a single block is representative of the overall MVD of the tumour. MVD was quantitated in one block per specimen of 60 lung tumours and nine normal lung tissues, and in 47 blocks taken from different regions of four tumours. Blood vessels were stained with antibody to von Willebrand Factor and MVD was quantitated using two methods: average density throughout the section (a-MVD) and density in the most vascularized area or 'hot spot' (h-MVD). Similar h-MVD values were found in tumours and in normal bronchus, whereas a-MVD was greater in the latter (P < 0.01). When 47 blocks from four tumours were analysed, inter-tumour variation was significant (P < 0.001) in spite of significant intra-tumour variation. The highest MVD value was not necessarily found in the periphery of the tumour. The four tumours were ranked into either two or four tiers according to their overall MVD. In 50 random selections of one block per tumour, the correct ranking was achieved in 68-74% of cases with the two-tier ranking and in 6-16% of cases with the four-tier ranking (h-MVD and a-MVD values respectively). These results suggest that elevated MVD values do not necessarily represent angiogenesis in non-small cell lung carcinomas. When only one block per tumour is examined, the chance of obtaining an accurate estimate of the vascularity of that tumour may be lower than 68%.