Microvessel density for melanoma prognosis

Functional Surgery for Subungual Melanoma: Surgical Tips Based on Histological Analysis of 21 Cadavers

BACKGROUND

Amputation has been the standard treatment for subungual melanoma. Although there is growing attention toward a more conservative functional surgery, specific operative techniques are not yet available.

OBJECTIVE

We aimed to provide objective measurements for use in functional surgery by analyzing the anatomy of the nail apparatus obtained from 21 cadavers.

MATERIALS AND METHODS

Nailbed thickness was histologically measured in each subunit, and skin surface anatomy was evaluated to determine the proximal resection margin. Immunohistochemical staining was performed to analyze microvessel distribution according to the nail subunit.

RESULTS

The nailbed thickness was the thinnest at the most proximal point of the nail matrix (thumbs, 1.10 ± 0.42 mm; big toes, 1.15 ± 0.37 mm) and the thickest at the hyponychium (thumbs, 2.86 ± 0.82 mm; big toes, 2.72 ± 0.84 mm). The distance from the eponychium to the skin surface closest to the bony cortex of extensor tendon insertion was 6.92 ± 5.13 mm in thumbs and 5.14 ± 1.59 mm in big toes. The median microvessel density was the highest at the hyponychium (25.74 vessels/mm2) and lowest at the germinal matrix (16.26 vessels/mm2) (p < .05).

CONCLUSION

This histological study offers practical tips, including those to help decide the proximal and deep resection margins, in functional surgery.

sFRP2 Supersedes VEGF as an Age-related Driver of Angiogenesis in Melanoma, Affecting Response to Anti-VEGF Therapy in Older Patients

PURPOSE

Angiogenesis is thought to be critical for tumor metastasis. However, inhibiting angiogenesis using antibodies such as bevacizumab (Avastin), has had little impact on melanoma patient survival. We have demonstrated that both angiogenesis and metastasis are increased in older individuals, and therefore sought to investigate whether there was an age-related difference in response to bevacizumab, and if so, what the underlying mechanism could be.

EXPERIMENTAL DESIGN

We analyzed data from the AVAST-M trial of 1,343 patients with melanoma treated with bevacizumab to determine whether there is an age-dependent response to bevacizumab. We also examined the age-dependent expression of VEGF and its cognate receptors in patients with melanoma, while using syngeneic melanoma animal models to target VEGF in young versus old mice. We also examined the age-related proangiogenic factor secreted frizzled-related protein 2 (sFRP2) and whether it could modulate response to anti-VEGF therapy.

RESULTS

We show that older patients respond poorly to bevacizumab, whereas younger patients show improvement in both disease-free survival and overall survival. We find that targeting VEGF does not ablate angiogenesis in an aged mouse model, while sFRP2 promotes angiogenesis in vitro and in young mice. Targeting sFRP2 in aged mice successfully ablates angiogenesis, while the effects of targeting VEGF in young mice can be overcome by increasing sFRP2.

CONCLUSIONS

VEGF is decreased during aging, thereby reducing response to bevacizumab. Despite the decrease in VEGF, angiogenesis is increased because of an increase in sFRP2 in the aged tumor microenvironment. These results stress the importance of considering age as a factor for designing targeted therapies.

Adjuvant therapy with pegylated interferon-alfa2b vs observation in stage II B/C patients with ulcerated primary: Results of the European Organisation for Research and Treatment of Cancer 18081 randomised trial

BACKGROUND

Subgroup analyses of two large EORTC adjuvant interferon-alpha2b (IFNα-2b) vs observation randomised trials demonstrated that a treatment benefit was observed only in patients with an ulcerated melanoma without palpable nodes (hazard ratio [HR] for recurrence-free survival [RFS] was 0.69). This was confirmed by a meta-analysis of 15 adjuvant IFN trials (HR: 0.79).

PATIENTS AND METHODS

In the EORTC 18081 trial, sentinel node-negative stage II patients with an ulcerated primary melanoma were 1:1 randomised between pegylated (PEG)-IFNα-2b at 3 μg/kg/week subcutaneously and observation, for 2 years, or until disease recurrence or unacceptable toxicity in spite of dose adjustments to maintain an Eastern Cooperative Oncology Group performance status of 0 or 1. Main end-point was RFS. Secondary end-points included distant metastasis-free survival (DMFS), overall survival, and safety (EudraCT Number: 2009-010273-20).

RESULTS

Between February 2013 and January 2017, only 112 patients were randomised, 56 in each arm. The trial was stopped early for lack of recruitment. At a 3.4-year median follow-up, the estimated HR for the PEG-IFNα-2b group compared with the observation group regarding RFS was 0.66 (95% confidence interval [CI]: 0.32-1.37), and the 3-year RFS rate was 80.0% (95% CI: 65.7-88.8%) and 72.9% (95% CI: 58.3-83.0%), respectively. DMFS was prolonged: HR: 0.39 (95% CI: 0.15-0.97), and the 3-year DMFS rate was 90.6% (95% CI: 78.9-96.0%) vs 76.4% (95% CI: 62.1-85.9%). One patient in the PEG-IFNα-2b group died compared with 4 in the observation group. Fifty-four patients started PEG-IFNα-2b treatment, 16 (29%) completed 2 years of treatment, 2 (4%) stopped due to recurrence, 23 (43%) due to toxicity and 14 (25%) due to other reasons.

CONCLUSIONS

The EORTC 18081 PEG-IFNα-2b randomised trial, observed a similar HR (0.69) for RFS as the previous EORTC trials (0.69). In countries without access to new drugs, adjuvant (PEG)-IFNα-2b treatment is an option for patients with ulcerated melanomas without palpable nodes.

Upregulation of intratumoral HLA class I and peritumoral Mx1 in ulcerated melanomas

Before the era of immune checkpoint blockade, a meta-analysis encompassing fifteen trials reported that adjuvant IFN-α significantly reduces the risk of relapse and improves survival of ulcerated melanoma (UM) with no benefit for higher doses compared to lower doses. IFNa2b affects many cell intrinsic features of tumor cells and modulates the host innate and cognate immune responses. To better understand the biological traits associated with ulceration that could explain the efficacy of prophylactic type 1 IFN, we performed immunohistochemical analysis of various molecules (major histocompatibility complex class I and class II, MX Dynamin Like GTPase 1 (MX1), inducible Nitric-Oxide Synthase (iNOS) or CD47) in two retrospective cohorts of melanoma patients, one diagnosed with a primary cutaneous melanoma (1995-2013, N = 172, among whom 49% were ulcerated melanoma (UM)) and a second one diagnosed with metastatic melanoma amenable to lymph node resection (EORTC 18952 and 18991 trials, N = 98, among whom 44% were UM). We found that primary and metastatic UM exhibit higher basal expression of MHC class I molecules, independently of Breslow thickness, histology and lymphocytic infiltration compared with NUM and that primary UM harbored higher constitutive levels of the antiviral protein Mx1 at the border of tumor beds than NUM. These findings suggest that UM expand in a tumor microenvironment where chronic exposure to type 1 IFN could favor a response to exogenous IFNs.

Correlation of microvascular density and proliferation index in undifferentiated nasopharyngeal carcinoma

Background: Undifferentiated nasopharyngeal carcinoma is a highly malignant tumor with an endemic distribution. Several histologic parameters have been studied to provide prognostic information for patient management. Both proliferation index and microvascular density are commonly determined on such tumors, but the relationship between these two parameters has not been studied fully. Objectives: Determine the association between microvascular density and cellular proliferation in undifferentiated nasopharyngeal carcinoma. Methods: A series of 60 cases were studied in patients of Southeast Asian origin. Cellular proliferation was determined using Ki67 immunostaining, and vessel proliferation using CD31 immunostaining in terms of areas of increased staining (‘hot spots’). Ki67 results were scored on a scale of 0-4+ and CD31 results as a microvascular density/mm2. Results: The mean of the microvascular density was 22/mm2 in the Ki67-negative group (25 cases). In the Ki67- positive group (35 cases), the mean was 35/mm2. The difference between the positive and negative group was statistically significant (p <0.001). Microvascular density significantly increased as the Ki67 score increased (p<0.001). However, the ‘hot spots’ for microvascular density in tissue sections did not correspond to areas of increased cellular proliferation. Conclusion: Pathologists usually determine only one of these two prognostic factors when dealing with undifferentiated nasopharyngeal carcinoma. The proliferation index is suggested because it is easier to perform and can be done on small biopsies not to contain enough surface area for microvascular density determination.

Wild-type KRAS is a novel therapeutic target for melanoma contributing to primary and acquired resistance to BRAF inhibition

Malignant melanoma reveals rapidly increasing incidence and mortality rates worldwide. By now, BRAF inhibition is the standard therapy for advanced melanoma in patients carrying BRAF mutations. However, only approximately 50% of melanoma patients harbor therapeutically attackable BRAF mutations, and overall survival after treatment with BRAF inhibitors is modest. KRAS (Kirsten Rat sarcoma) proteins are acting upstream of BRAF and have a major role in human cancer. Recent approaches awaken the hope to use KRAS inhibition (KRASi) as a clinical tool. In this study, we identified wild-type KRAS as a novel therapeutic target in melanoma. KRASi functions synergistically with BRAF inhibition to reduce melanoma proliferation and to induce apoptosis independently of BRAF mutational status. Moreover, acquired resistance to BRAF inhibitors in melanoma is dependent on dynamic regulation of KRAS expression with subsequent AKT and extracellular-signal regulated kinase activation and can be overcome by KRASi. This suggests KRASi as novel approach in melanoma-alone or in combination with other therapeutic regimes.

Microvessel Density in Patients with Cutaneous Melanoma: An Up-to-Date Systematic Review and Meta-Analysis

Background

We conducted a meta-analysis, in order to appraise the effect of microvessel density (MVD) on the survival of patients with cutaneous melanoma.

Methods

This study was conducted according to the PRISMA guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. A systematic literature search in electronic databases (MEDLINE, Web of Science, and Cochrane Central Register of Controlled Clinical Trials) was performed. Fixed Effects or Random Effects model was used, based on the Cochran Q test.

Results

In total 9 studies (903 patients) were included. Pooled HR for overall survival (OS) and disease-free survival (DFS) were 2.62 (95% CI: 0.71–9.60, p = 0.15) and 2.64 (95% CI: 0.82–8.47, p = 0.10), respectively. Odds ratios of overall survival between high and low MVD groups, at 12 (1.45, 95% CI: 0.16–13.24), 36 (2.93, 95% CI: 0.63–13.59), and 60 (4.09, 95% CI: 0.85–19.77) months did not reach statistical significance. Significant superiority of low MVD group, in terms of DFS, at all time intervals (OR: 4.69, p < 0.0001; OR: 2.18, p = 0.004; OR: 7.46, p = 0.01, resp.) was documented.

Discussion

MVD does not affect the HR of OS and DFS. A strong correlation with DFS rates at 12, 36, and 60 months was recorded.

Angiogenesis in Dermatology - Insights of Molecular Mechanisms and Latest Developments

Angiogenesis is the growth of new blood vessels from pre-existing vessels. It is a biological process essential in physiological wound healing or pathological inflammation and tumor growth, which underlies a complex interplay of stimulating and inhibiting signals. Extracellular matrix, cells of innate and adaptive immunity and endothelial cells itself are a major source of angiogenic factors that activate or inhibit specific receptors and consequently influence intracellular signaling pathways. Most inflammatory and neoplastic diseases in dermatology are characterized by excessive angiogenesis, such as psoriasis, atopic dermatitis, as well as melanoma, non-melanoma skin cancer, but also benign vascular neoplasia. In this article we describe current knowledge of angiogenesis and its most relevant mechanisms in different dermatological disorders with particular emphasis on the angiogenic factors (vascular endothelial growth factor) and angiopoietins as a target of current and future directions of anti-angiogenic therapy.

Evaluations of the Renal Cell Carcinoma Model Caki-1 Using a Silicon Based Microvascular Casting Technique

The vascular development of orthotopically grown human renal cell carcinoma (Caki-1) was examined using a silicon based casting technique in nude mice. Images taken of these vascular casts showed Caki-1 tumors to be highly vascularized and invasive. The spread of the tumor within the cortex of the kidney revealed that Caki-1 recruits the kidney's own vasculature, destroying the functional glomeruli in the process. The loss of these glomeruli was further highlighted by the presence of enlarged glomeruli resulting from the development of super nephrons. Vessel size and density measurements were then made in this model. This was done using both computer-based and manual measurement methods. In the vessel size studies the computer-based method tended to overestimate the number of larger diameter vessels whereas the vessels density assessment showed good agreement between the two techniques. Nevertheless, both methods showed that Caki-1 tumors possessed a higher proportion of larger diameter vessels and a lower vessel density than normal kidney cortex.

In summary, silicon based vascular casting proved to be a simple and effective tool for the study of tumor vasculature. In particular this technique could readily be used to examine the invasion of tumor into normal tissue. The computer-based technique for evaluating vessel number and vascular density was found to have merit in both normal and tumor tissues, particularly in the vascular density studies. However, in both settings this technique did tend to overestimate the number of larger diameter vessels.

Microvessel density, lymphovascular density, and lymphovascular invasion in primary cutaneous melanoma-correlation with histopathologic prognosticators and BRAF status

The relationship between microvessel density (MVD), lymphovascular density (LVD), and lymphovascular invasion (LVI) in primary cutaneous melanoma (PCM) remains unclear. Given this, a total of 102 PCMs were assessed for MVD (vascular endothelial growth factor receptor 2 and Endocan), LVD (D2-40), and LVI (immunostaining with D2-40/S-100 and hematoxylin and eosin); tumoral S-100A13, vascular endothelial growth factor receptor 2, and Endocan; and BRAF status. LVD was associated with MVD (P = .01). MVD was higher in PCMs with depth greater than or equal to 2 mm and ulceration (P = .04, .05), whereas LVD was higher in PCMs with depth greater than or equal to 2 mm and mitoses (P = .03, .02). After adjusting for MVD and LVD, only ulceration was associated with LVI (P < .02). A BRAF mutation was seen in 30.4% cases, and when present, both LVD and host response (P = .0008 and .04, respectively) were significantly associated with MVD. Immunostaining with S-100A13 was noted in 99% of cases and a significant association noted only with ulceration (P = .05). Immunostaining increased LVI positivity (46.5% versus 4.9% by hematoxylin and eosin, P < .0001). MVD and LVD are not associated with LVI, appear to be closely related with each other, and are associated with select markers of poor prognosticative value. The association between a host response and LVD and MVD in PCMs with a BRAF mutation suggests that they exhibit potential for strategizing immunotherapies.

Blood microvessel density, lymphatic microvessel density and lymphatic invasion in predicting melanoma metastases: systematic review and meta-analysis

In malignant melanoma (MM) there is an urgent need to identify new markers with predictive value superior to the traditional clinical and histological parameters. Angiogenesis and lymphangiogenesis have been recognized as critical processes in tumour growth and metastasis development, and numerous studies have evaluated the significance of these parameters in predicting the prognosis in solid tumours, including MM. We set out to determine whether angiogenesis, lymphangiogenesis and lymphatic invasion (LI) are valuable prognostic markers in MM. We systematically reviewed the available literature and subsequently performed a meta-analysis on the compiled data. To be eligible for the systematic review, a study had to provide the microvessel density (MVD), the lymphatic vessel density (LVD) or information about LI, assessed by immunohistochemistry on the primary site in patients with MM. To be evaluable for the meta-analysis, a study also had to provide information on clinical outcome. We approached selected studies with the Reporting recommendations for tumour marker (REMARK) criteria, verifying whether they had followed the recommendations. In total, nine angiogenesis, seven lymphangiogenesis and 10 LI studies were included in our meta-analysis, representing 419, 474 and 802 patients, respectively. Using meta-analysis, we showed that peritumoral LVD and the presence of LI have prognostic value for patients with MM. In contrast, MVD and intratumoral LVD did not have prognostic value in these patients. LVD and LI seem to have prognostic value for patients with MM.

The clinicopathological and gene expression patterns associated with ulceration of primary melanoma

Ulceration of primary melanomas is associated with poor prognosis yet is reported to predict benefit from adjuvant interferon. To better understand the biological processes involved, clinicopathological factors associated with ulceration were determined in 1804 patients. From this cohort, 348 primary tumor blocks were sampled to generate gene expression data using a 502-gene cancer panel and 195 blocks were used for immunohistochemistry to detect macrophage infiltration and vessel density. Gene expression results were validated using a whole genome array in two independent sample sets. Ulceration of primary melanomas was associated with more proliferative tumors, tumor vessel invasion, and increased microvessel density. Infiltration of tumors with greater number of macrophages and gene expression pathways associated with wound healing and up-regulation of pro-inflammatory cytokines suggests that ulceration is associated with tumor-related inflammation. The relative benefit from interferon reported in patients with ulcerated tumors may reflect modification of signaling pathways involved in inflammation.

Mechanisms of tumour vascularization in cutaneous malignant melanoma: clinical implications

Malignant melanoma represents < 10% of all skin cancers but is responsible for the majority of skin-cancer-related deaths. Metastatic melanoma has historically been considered as one of the most therapeutically challenging malignancies. Fortunately, for the first time after decades of basic research and clinical investigation, new drugs have produced major clinical responses. Angiogenesis has been considered an important target for cancer treatment. Initial efforts have focused primarily on targeting endothelial and tumour-related vascular endothelial growth factor signalling. Here, we review different mechanisms of tumour vascularization described in melanoma and discuss the potential clinical implications.

Lymphangiogenesis and its correlation with the VEGF expression and the sentinel lymph node in cutaneous melanomas

The aim of the study is to evaluate the density of intratumoral and peritumoral lymphatic vessels in primary cutaneous melanomas and to assess their correlation with the status of sentinel lymph nodes and the VEGF expression in tumor cells and stromal cells. A total of 40 patients were enrolled in the study: the melanomas were radically excised with the extirpation of the sentinel lymph node. The study subjects were divided into two groups: 20 cases with positive and 20 cases with negative sentinel lymph node results. The density of lymphatic vessels was evaluated by the antibody D2-40 and the VEGF expression was investigated in the semiquantitative way. The VEGF expression in melanoma cells and the stromal cells was negative to variable positive at both SLN negative and SLN positive patients in all pT stages. In the group of SLN positive patients, the density of intratumoral lymphatic vessels was low up to moderate, while it was observed to be absent, somewhere on the low level in the group of SLN negative patients. On the other side, the density of peritumoral lymphatic vessels was equally numerous at both SLN negative and SLN positive patients. The lymphatic invasion was found out at 4 SLN positive patients only. The ulceration was chiefly in the group of LN positive patients. The results show that the density of lymphangiogenesis and the intensity of the VEGF expression are considered to be an unreliable predictor of melanoma metastasis to the sentinel lymph node, but the ulceration and the lymphatic invasion can predict the potential for metastasis.

Chalkley method in the angiogenesis research and its automation via computer simulation

The aim of this study was to develop a computer simulation evaluating microvessel density according to the Chalkley method on digital images taken from neovascular hot spots. An image analysis algorithm has been developed using ImageJ, an extensible, open source image processing and analysis software. The idea was to create a virtual Chalkley point array graticule, and to calculate Chalkley counts automatically by stepwise angular rotation of it on the superimposed images containing properly segmented microvessels. This eliminates the necessity of having the Chalkley graticule, an accessory that has to be mounted on the microscope's ocular. The proposed method is a faithful simulation of the original Chalkley counting procedure. It gives pathologists who do not have the Chalkley graticule an opportunity to evaluate microvessels quantitatively according to the basic principles underlying Chalkley counting. Evaluating microvessel densities in solid tumors is a frequent procedure in angiogenesis research. A few standard methods, including Chalkley counting, are used for the estimation of microvessel density. Several independent studies have shown that the Chalkley counting is more consistent and may provide useful data on prognosis. The obvious disadvantages lie in the facts that this method is time-consuming and requires a special hardware. Computer simulation may overcome these obstacles.

Microvascular lymphatic density analysis in cutaneous regressive and nonregressive superficial spreading melanomas using the lymphatic marker D2-40

BACKGROUND

The prognostic significance of spontaneous regression in melanoma, especially thin lesions, has been a controversial issue for the past 20 years, although recent studies suggest that extensive and late regression may be related to worse prognosis. Many data suggest that lymphangiogenesis predicts metastatic spread in melanoma.

METHODS

We have quantified lymphatic microvascular density (LMVD) in thin (≤ 1.0 mm) superficial spreading melanomas comparing regressive and nonregressive melanomas, regressive and nonregressive areas from the same tumor, and early and late histological stages of regression in the same tumor. In addition, we tried to correlate lymphangiogenesis and tumor growth phase. We conducted histological examinations and immunohistochemical analyses using monoclonal antibody D2-40 with subsequent quantification by image analysis of 37 melanomas, 16 regressive and 21 nonregressive (controls).

RESULTS

We found higher LMVD in the late stage of regression compared with nonregressive area (internal control) of regressive melanomas.

CONCLUSIONS

Our study suggest that the late stage of spontaneous regression in thin melanomas may be related to worse prognosis as it showed higher LMVD, and evidence shows that this is related with increased risk of metastatic spread. But this supposition must be confirmed by a longer follow-up for detection of lymph node metastases.

Systemic treatment of metastatic melanoma: new approaches

The field of melanoma therapeutics has experienced a dramatic paradigm shift over the last 12 months through recent discoveries of novel therapeutics targeting known oncogenes and immunotherapeutic antibodies. In this article, we review these findings and provide a framework to understand these discoveries, their significance in melanoma therapy, and role in clinical care. As this understanding grows, enduring therapeutic success may be achieved through tailored use of molecular markers and immunotherapies in sequential or combinatorial methods.

Stromal impact on tumor growth and lymphangiogenesis in human carcinoma xenografts

Squamous cell carcinomas (SCCs) arising in the oral cavity are associated with poor survival, mainly due to metastatic disease. In contrast, skin SCCs rarely metastasize and are usually curable. To study influence of tongue and skin stroma on cancer growth and induction of lymphangiogenesis, xenograft tumors of human carcinoma cells were established either in tongue or skin of BALB/c nude mice. Two oral and two skin SCC cell lines were used, as well as an endometrial adenocarcinoma cell line. Tongue tumors established from all cell lines were larger than corresponding skin tumors. Peritumoral lymphatic vessel density was up to five times higher in tongue than in corresponding skin tumors, and mRNA level of the lymphangiogenic growth factor vascular endothelial growth factor (VEGF)-C was twice as high in tongue tumors compared with corresponding skin tumors. Contrary to lymphatic vessel density, blood vessel density was higher in skin tumors than in tongue tumors. In a cohort of patient samples, lymphatic vessel density was found to be higher in tongue SCCs compared with skin SCCs, supporting a clinical relevance of our findings. Our results show that the tumor stroma has a profound impact on cancer growth and induction of lymphangiogenesis and angiogenesis. The difference in lymphatic vessel density between tongue and skin tumors may be important in directing metastatic potential of tumors arising in these organs.

Melanoma prognostic factors found in the dermatopathology report

Significant prognostic information is available in a routine melanoma dermatopathology report. Features that are enumerated in the pathology report and that portend a potentially poorer prognosis are older age, site (acral, head, neck), male sex, increasing Breslow tumor thickness, increasing Clark's level, ulceration, increasing number of mitoses, vertical growth phase, regression, absence of a host inflammatory response, increased tumor vascularity, angiotropism, vascular invasion, neurotropism, marked atypia, and satellite metastasis.

Vascular density has prognostic value in Merkel cell carcinoma

Merkel cell carcinomas are aggressive tumours for which histological prognostic factors need to be established. This study examines the prognostic role of vascular density, based on CD34 immunohistochemical staining in Merkel cell carcinoma. Thirty-six cases of Merkel cell carcinoma were immunohistochemically stained for the endothelial marker CD34. Vascular density was assessed in the tumor and stroma with a Chalkley eyepiece graticule. The scores of vascular density were correlated with other clinical and histological parameters to determine the prognostic significance of tumor vascularity. Increased vascular density was shown to be significantly associated with a worse prognosis (P = 0.005). A 1-unit increase in total vessel score was associated with a 3.9 times increase in the risk of death (95% hazard ratio confidence limits 1.50-10.32). Other factors associated with a worse outcome included tumor size (P = 0.05), the presence of lymphovascular invasion (P = 0.03), and tumor mast cell count (P < 0.002). Increased vascular density is associated with a worse prognosis in Merkel cell carcinomas. Assessment of vascular density may assist in predicting clinical behavior in these tumors and in evaluating the effects of adjuvant therapy.

Enhanced Antitumor Efficacy of Clinical-Grade Vasculature-Targeted Liposomal Doxorubicin

Purpose: In vivo evaluation of good manufacturing practice-grade targeted liposomal doxorubicin (TVT-DOX), bound to a CD13 isoform expressed on the vasculature of solid tumors, in human tumor xenografts of neuroblastoma, ovarian cancer, and lung cancer.

Experimental Design: Mice were implanted with lung, ovarian, or neuroblastoma tumor cells via the pulmonary, peritoneal, or orthotopic (adrenal gland) routes, respectively, and treated, at different days post inoculation, with multiple doses of doxorubicin, administered either free or encapsulated in untargeted liposomes (Caelyx) or in TVT-DOX. The effect of TVT-DOX treatment on tumor cell proliferation, viability, apoptosis, and angiogenesis was studied by immunohistochemical analyses of neoplastic tissues and using the chick embryo chorioallantoic membrane assay.

Results: Compared with the three control groups (no doxorubicin, free doxorubicin, or Caelyx), statistically significant improvements in survival was seen in all three animal models following treatment with 5 mg/kg (maximum tolerated dose) of TVT-DOX, with long-term survivors occurring in the neuroblastoma group; increased survival was also seen at a dose of 1.7 mg/kg in mice bearing neuroblastoma or ovarian cancer. Minimal residual disease after surgical removal of neuroblastoma primary mass, and the enhanced response to TVT-DOX, was visualized and quantified by bioluminescence imaging and with magnetic resonance imaging. When treated with TVT-DOX, compared with Caelyx, all three tumor models, as assayed by immunohistochemistry and chorioallantoic membrane, showed statistically significant reductions in cell proliferation, blood vessel density, and microvessel area, showing increased cell apoptosis.

Conclusion: TVT-DOX should be evaluated as a novel angiostatic strategy for adjuvant therapy of solid tumors.

Chapter 14. Measuring intratumoral microvessel density

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

Prominent microvascular proliferation in clinically aggressive neuroblastoma

PURPOSE

Tumor vasculature is disorganized and glomeruloid microvascular proliferation (MVP) has been identified as a poor prognosticator in some adult cancers. To determine the clinical significance of MVP, including glomeruloid MVP in neuroblastoma, we initially examined vessel architecture in tumor sections from 51 children diagnosed at Children's Memorial Hospital (CMH) and subsequently evaluated 154 neuroblastoma tumors on a tissue microarray constructed at Children's Hospital of Philadelphia (CHOP).

EXPERIMENTAL DESIGN

H&E sections were examined for the presence of structurally abnormal vessels and further characterized by immunostaining for CD31 and von Willebrand factor to highlight endothelial cells and alpha-smooth muscle actin for pericytes. Tumors with thickened walls containing a complete layer of hypertrophic endothelial cells plus additional layers of vascular mural cells were classified as MVP positive. Associations between MVP and established clinicopathologic features and outcome were assessed.

RESULTS

In both series, MVP was significantly associated with Schwannian stroma-poor histology (CMH, P = 0.008; CHOP, P < 0.001) and decreased survival probability (CMH, P = 0.017; CHOP, P = 0.014). In the CHOP series, MVP was associated with high-risk group classification (P < 0.001), although this association was not seen in the smaller CMH cohort.

CONCLUSIONS

The association between MVP and poor outcome provides further support for the concept that angiogenesis plays an important role in determining the biological behavior of neuroblastoma tumors. Our results also indicate that angiogenesis is regulated differently in Schwannian stroma-rich versus stroma-poor neuroblastoma tumors. Further studies investigating the activity of angiogenic inhibitors in children with clinically aggressive stroma-poor neuroblastoma are warranted.

Immunoexpression of endoglin in brain metastasis secondary to malignant melanoma: evaluation of angiogenesis and comparison with brain metastasis secondary to breast and lung carcinomas

Brain metastases are linked to poor prognosis. After carcinomas of the lung and breast, malignant melanomas (MM) are the next type of neoplasm with the higher metastatic dissemination involving the central nervous system and that has the worst prognosis after metastasis has been diagnosed. Angiogenesis has been linked to tumor growth and metastasis. Among the immunomarkers of angiogenesis, endoglin (CD105) is the most specific antibody, since it is a marker for tumor endothelium, and expression of CD105 has been observed to be associated with prognosis in several types of tumor, which is not always observed in melanomas. This study investigated angiogenesis in brain metastasis secondary to malignant melanomas and compared these with brain metastasis secondary to carcinomas of the lung and breast, through expression of CD105 (endoglin). The study investigated 93 cases of brain metastasis secondary to MM (33) and carcinomas of the lung (31) and breast (29), assessing endoglin immunoexpression, number of microvessels and diameter of tumor vessels. Tumor microvessels were counted using a modified version of the Chalkley technique. The observed difference between MM and breast carcinoma was statistically significant (P = 0.026). The difference between MM and lung carcinoma was not significant (P = 0.218). Vascular diameter observation revealed no statistical difference between the vascular size of neoplastic vessels in MM and in breast and lung carcinomas. Of the tumors investigated here, malignant melanomas were shown to have the lowest number of microvessels and had intermediate tumor vessel diameter as compared to carcinomas of the lungs and breast. Such results were not expected to be found in neoplasms such as melanomas that, besides presenting high dissemination capacity, have a high index of hemorrhage secondary to brain metastasis.

Association of microvessel density with infiltrating cells in human cutaneous malignant melanoma

Vascularization and host response to malignant tumors may have common molecular regulators, therefore, we analyzed the relationship between microvessel density (MVD) and tumor infiltrating cells in cutaneous malignant melanoma. Density of lymphocyte subpopulations, macrophages, dendritic cells and CD34(+) microvessels was determined by immunohistochemistry in primary tumor samples from fifty-two patients with melanoma thicker than 1 mm. Intratumoral MVD did not show significant association with infiltration for any of these cell types. In the case of peritumoral reactive cell densities analyzed in the whole patient population, a positive correlation of MVD was found with CD3(+) T cell density. This association was stronger in melanomas >4.0 mm and in visceral metastatic tumors. In these subgroups similar phenomenon was observed for CD8(+) cells. We found significant correlation of MVD with CD68(+) macrophage density only in the highest thickness category, and weak associations with B-cell and dendritic cell infiltration in visceral metastatic cases. MVD did not vary significantly in tumors categorized according to thickness, localization, ulceration or histological type. However, both intratumoral MVD and macrophage infiltration were significantly higher in male patients compared to females. The correlation of immune cell density with tumor vascularization and gender differences in vascularity and macrophage infiltration of melanoma deserve further attention.