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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent evidence suggests that angiogenesis, as assessed by vascular density, may be an independent prognostic factor in breast carcinoma. The authors chose to examine this hypothesis further using two different methods, both using an immunohistochemical technique to assess vascularity. In the first, tissue sections from 93 patients with human breast carcinoma were immunostained for the endothelial antigen CD 34. Fields were selected at random in sections stained with the monoclonal antibody QBEnd/10, and both the number of blood vessels and percentage of endothelial cells per unit area measured using an interactive image analysis system (SEESCAN). In the second, an additional 72 patients were added and the 165 sections immunostained for CD31 (PECAM 1) using the monoclonal antibody JC 709. The area of highest vascular density was then identified and measured. A statistically significant correlation was found between percentage endothelial area and tumor type (P < .03) using the first method, and, for lymph node-negative patients only, between vascular density and tumor type (P < .02) using the second method. There was no correlation with lymph node status, recurrence, distant metastases, or overall survival using either method (minimum follow-up 12 years). The authors conclude that the evaluation of tumor angiogenesis using these methods does not provide additional prognostic information in this group of patients.
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PMID:Assessment of angiogenesis in breast carcinoma: an important factor in prognosis? 759 Jun 87

Current studies of tumor angiogenesis rely on the concept that endothelium proliferates 30-40 times faster in tumors than in normal tissues. This evidence is based on histological autoradiographic data largely from animal studies. To assess endothelial cell proliferation in human cancer we used the more sensitive and specific technique of immunohistochemistry. We measured the frequency and distribution of endothelial cell proliferation and examined their relationship to tumor cell proliferation. For the first time, we also correlated endothelial and tumor cell proliferation with tumor vascularity. Twenty breast carcinomas from patients exposed to bromodeoxyuridine 3-8 h prior to surgery were double immunostained using antibodies to CD31 (as a marker of endothelium) and bromodeoxyuridine (as a marker of proliferation). The labeling index (LI) for both tumor and endothelial cells was determined and tumor vascularity was assessed by counting the number of CD31 positive vessels. Endothelial cell proliferation was predominantly at the tumor periphery while tumor cell proliferation occurred throughout the lesion. The mean LIs for endothelium and tumor were 2.2% (range, 0.8-5.3) and 7.3% (range, 1.3-17.1), respectively. There was no correlation between tumor and endothelial cell LI (P = 0.414) or between the tumor LI or endothelial cell LI and tumor vascularity (P = 0.08 and P = 0.39, respectively). These findings suggest that previous studies in animal tumors have significantly overestimated endothelial cell proliferation and that its importance in tumor angiogenesis may be related more to continual remodeling and migration of vessels than to proliferation alone.
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PMID:Relationship of endothelial cell proliferation to tumor vascularity in human breast cancer. 768 28

Twenty-nine tumors (from 26 patients, including two with recurrent disease) diagnosed as solitary fibrous tumor (SFT) of the pleura (n = 23), mediastinum (n = 4), abdominal cavity (n = 1), and parotid gland (n = 1) were studied immunohistochemically. Three histologically malignant tumors showed areas of high cellularity and mitotic activity (more than 4 mitoses/10 high-power fields) with features resembling malignant fibrous histiocytoma, malignant hemangiopericytoma, or fibrosarcoma, together with areas typical of benign solitary fibrous tumor. Formaldehyde-fixed, paraffin-embedded tissues and avidin-biotin-complex immunostaining were used. All of the tumors showed vimentin positivity and did not stain for cytokeratin, glial fibrillary acidic protein, or muscle cell markers, except for focal desmin reactivity in seven tumors, mostly seen in frozen sections, and focal keratin reactivity in one histologically malignant tumor. The neoplastic cells were positive for CD34 and negative for CD31; these patterns also were seen in the three histologically malignant cases. In nine of the cases acetone-fixed frozen sections showed variable focal positivity for neurofilament proteins of 68 kd. We conclude that SFT is a neoplasm of fibroblasts/primitive mesenchymal cells with features of multidirectional differentiation. We also report the finding of a novel site for SFT, the parotid gland.
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PMID:Solitary fibrous tumor: histological and immunohistochemical spectrum of benign and malignant variants presenting at different sites. 770 24

The distribution of PECAM-1/CD31 molecule was investigated in 133 breast carcinomas using monoclonal antibody and frozen sections. Anti-CD31 labels endothelial cells and reflects stromal angiogenesis. The CD31 immunoreactivity was evaluated by computer-assisted analysis of digitized microscopic images. The automatic screening of the whole preparation and the measurements of the mean CD31 immunostained surface was performed in each case. A similar procedure was achieved for p53, cathepsin D, P-gp, pHER-2/neu, Ki67, pS2 estrogen and progesterone antigenic sites immunodetection. The image analysis of positive CD31 surface was variable, ranging from 4% to 33% (mean 14.7%, SD = 5.43). The CD31 positive surface correlated (P < .01) with the Nottingham prognostic index, but not with the tumor size, the node status, the tumor grade, nor with the patient age. Also the CD31 immunoreactivity was independent of the pHER-2/neu, Ki67 antigen, p53, ER, PR and pS2 immunodetectable expression in tumors, but correlates with that of cathepsin D (P = .024) and P-gp (P = .028), which reflects the multi-drug resistance capacity of tumor cells. In conclusion, CD31 positive vessels assessed on frozen sections by image analysis constitute an excellent method of evaluating tumor stromal angiogenesis, and can be further used for clinical purposes. The results also suggest that the CD31/PECAM molecule may be involved in the spread of tumor by interacting with extracellular matrix lysis that results from the tumor cell proteasic activity and with multidrug resistance.
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PMID:CD31 quantitative immunocytochemical assays in breast carcinomas. Correlation with current prognostic factors. 772 41

Hemangiomas, localized tumors of blood vessels, appear in approximately 10-12% of Caucasian infants. These lesions are characterized by a rapid proliferation of capillaries for the first year (proliferating phase), followed by slow, inevitable, regression of the tumor over the ensuing 1-5 yr (involuting phase), and continual improvement until 6-12 yr of age (involuted phase). To delineate the clinically observed growth phases of hemangiomas at a cellular level, we undertook an immunohistochemical analysis using nine independent markers. The proliferating phase was defined by high expression of proliferating cell nuclear antigen, type IV collagenase, and vascular endothelial growth factor. Elevated expression of the tissue inhibitor of metalloproteinase, TIMP 1, an inhibitor of new blood vessel formation, was observed exclusively in the involuting phase. High expression of basic fibroblast growth factor (bFGF) and urokinase was present in the proliferating and involuting phases. There was coexpression of bFGF and endothelial phenotypic markers CD31 and von Willebrand factor in the proliferating phase. These results provide an objective basis for staging hemangiomas and may be used to evaluate pharmacological agents, such as corticosteroids and interferon alfa-2a, which accelerate regression of hemangiomas. By contrast, vascular malformations do not express proliferating cell nuclear antigen, vascular endothelial growth factor, bFGF, type IV collagenase, and urokinase. These data demonstrate immunohistochemical differences between proliferating hemangiomas and vascular malformations which reflect the biological distinctions between these vascular lesions.
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PMID:Cellular markers that distinguish the phases of hemangioma during infancy and childhood. 791 Nov 27

The MUC18 protein, a member of the immunoglobulin superfamily and related to several adhesion molecules, shows an expression pattern in human malignant melanoma which is closely associated with tumor progression and the onset of metastasis. To determine the expression pattern of MUC18 in normal human tissues, immunohistochemical analysis was performed on frozen sections of a variety of normal human tissues using monoclonal antibodies against three different epitopes. This analysis showed that expression of MUC18 is limited to smooth muscle cells and to vascular endothelium. No reactivity could be observed with epithelial cells or with quiescent or activated hemopoetic cells. Smooth muscle cells in lung, skin, and in the gastrointestinal tract express MUC18 as does vascular smooth muscle, whereas myocardium or skeletal muscle appeared negative. Comparison of MUC18 staining with that of the panendothelial marker CD31 showed that MUC18 is expressed on the endothelia of a subset of blood capillaries and in tumor vessels but is absent on the endothelium of arterial vessels and large veins. The regulation of MUC18 expression was investigated in vascular smooth muscle cells and endothelial cells cultured in vitro. These studies revealed induction of the gene in endothelial cells upon proliferation. The observation that the MUC18 protein is not only present on melanoma cells but also on the endothelia of blood vessels penetrating primary and metastatic melanomas suggests a complex involvement of this potential cell adhesion molecule in tumor angiogenesis and metastasis.
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PMID:MUC18, a melanoma-progression associated molecule, and its potential role in tumor vascularization and hematogenous spread. 792 17

The majority of cutaneous angiosarcomas display typical architectural features of irregular anastomosing vascular channels in the dermis and subcutis. Nuclei are usually hyperchromatic and pleomorphic but the volume of cytoplasm of the neoplastic cells is often small. Diagnosis can be made readily on an adequate biopsy. We recently experienced difficulty diagnosing an angiosarcoma composed predominantly of cells with abundant granular cytoplasm. We were able to compare the present case with sections obtained from the only other reported example. The architectural expression of an anastomosing vascular pattern in areas of tumor, combined with the positive staining for Factor VIII-related antigen (FVIIIRAg) and Ulex europaeus agglutinin-1 (UEA1) enabled us to make a diagnosis of angiosarcoma. The tumor failed to stain for the other endothelial markers (CD31 and CD34) which were positive in the original case. A marker for lysosomes (CD68) stained the granules in both cases. The granular cell variant of cutaneous angiosarcoma is very rare. Diagnosis is possible by recognizing the typical anastomosing neoplastic vascular channels at the periphery of the lesion, and by use of a combination of lectin (UEA1) and immunohistochemical (FVIIIRAg, CD34 and CD31) endothelial markers.
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PMID:Cutaneous granular cell angiosarcoma. 796 28

Angiogenesis is a major new prognostic factor in breast cancer. Small vessels quantitatively assessed by staining with anti-CD31 antibodies correlate with lymph node involvement and are a better independent predictor of survival. There are many vascular growth factors, but predominant in primary tumors assessed by nuclease protection assays are vascular endothelial growth factor and platelet-derived endothelial cell growth factor. Acidic and basic fibroblast growth factor are also detectable. A common feature of these angiogenic factors is heparin binding, so novel analogues of suramin that can compete for heparin binding have been developed. These are more potent in vitro against endothelial cells and are less toxic in vivo, thereby giving a much better therapeutic ratio. Protein kinase C is also important in endothelial growth, as it is in carcinoma growth. Thus, a novel agent inhibiting this pathway, and inducing transforming growth factor-beta production has been assessed in a Phase I trial; this agent is bryostatin. It does not cause marrow suppression and has stimulatory effects of tumor necrosis factor-alpha and interleukin (IL)-6 production. High expression of epidermal growth factor (EGF) receptors and erbB-2 has been related to poor prognosis. EGF receptors are mainly regulated by transcription, as are some cases of high erbB-2 expression. Thus, a novel approach to gene therapy is being developed using direct tumor injection of cDNA, with a tumor specific promoter ligated to the IL-2 gene. This avoids many problems associated with targeting. Because IL-2 stimulation of cytotoxic T-cells will depend on appropriate antigen presentation, human lymphocyte antigen Class I expression was studied, as was the peptide transporter system RING4 (TAP1). Losses were found in 50% of cases, and in some cases only in lymph nodes but not primary cancers, thereby providing evidence for a role in suppressing metastasis. Thus, many new approaches to therapy are possible as a result of understanding growth factors and intracellular signaling pathways.
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PMID:Gene therapy through signal transduction pathways and angiogenic growth factors as therapeutic targets in breast cancer. 803 35

Two monoclonal antibodies (mAb), MEC 7.46 (IgG1) and MEC 13.3 (IgG2a) that specifically recognize mouse endothelial cells (EC) of blood vessels, were produced immunizing a Lewis rat with a polyoma middle T transformed EC line. Antibodies were screened by enzyme-linked immunosorbent assay (ELISA) and by immunofluorescence on different cultured cell lines and by immunoperoxidase staining on frozen sections of various mouse normal and inflammatory tissues. Both mAbs reacted with eight transformed endothelial lines tested in vitro, but were consistently negative on various cell lines of different histological origin. Reactivity was not altered by preexposure of the cell lines to IL-1. Microscopic immunofluorescence analysis showed that the MEC mAbs localized at the cell-cell contacts in EC. Immunohistochemical staining of various mouse tissue was always restricted to the EC of all blood vessels of the organ considered. Staining of the endothelial lining of blood vessels was greater at cell-to-cell contacts. Weak reactivity was detected in bone marrow and spleen megakaryocytes. This picture was not altered in inflamed and tumor tissues. In the developing mouse embryo, MEC 13.3 specifically stained proliferating and sprouting endothelium in all organs and tissues examined. Both MEC 7.46 and MEC 13.3 mAbs were able to precipitate a molecule with an apparent molecular mass of 130 kDa from endothelioma lysates. The protein was synthesized by the cells and exposed on the cell surface. Immunodepletion analysis indicated that MEC 13.3 recognized a molecule related to the murine from of PECAM or CD31. We believe that these mAbs are promising tools for the identification of murine EC and for studying their ontogenesis and functions.
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PMID:Monoclonal antibodies specific for endothelial cells of mouse blood vessels. Their application in the identification of adult and embryonic endothelium. 808 49

Lymphokine-activated killer (LAK) cells are able to colonize sites of tumor lesions in mouse and man. The molecular mechanisms of homing in on tumors are largely unknown. However, before LAK cells can reach the tumor, they must adhere to the vascular endothelial within the lesion and then extravasate. We developed a novel mAb, EA-3, which recognizes the murine homologue of the human adhesion molecule CD31. It is present on a subpopulation of murine LAK cells and all endothelial cells. CD31 was also involved in the adhesion of LAK cells to endothelium. Since CD31 can initiate integrin activation by inside-out signaling after binding to its ligand, EA-3 was used to minimic this in adhesion assays. It induces modifications in the beta 2 integrin LFA-1, leading to increased binding capacities of the cells to endothelium. In contrast, beta 1 integrins and RGD-binding integrins were not affected. These results suggest that expression of CD31 might confer adhesive advantages for LAK cells prone to tumor infiltration.
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PMID:Murine platelet endothelial cell adhesion molecule (PECAM-1)/CD31 modulates beta 2 integrins on lymphokine-activated killer cells. 840 46


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