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

A neoangiogenic response is critical for the unrestricted growth of solid tumors beyond a few millimeters in diameter. Release of adequate growth-stimulating activity from tumor cells is obviously required for the stimulation of blood vessel growth, and blockade of such stimulatory activity should repress tumor growth at the microscopic level. To test this hypothesis and to study appropriate inhibitors, we used a human adrenal cancer cell line (SW-13/K-fgf) engineered to secrete Kaposi's sarcoma-derived fibroblast growth factor (K-FGF), which we previously showed to induce growth of highly vascularized subcutaneous tumors in animals by autocrine and paracrine stimuli. In the present study, we tested different polysulfates for their selective inhibition of proliferation induced by K-FGF versus proliferation independent of K-FGF. Suramin and dextran sulfate showed slight selective inhibition of K-FGF-induced proliferation, ie, inhibition three- and five-fold greater, respectively, than the inhibition of proliferation independent of K-FGF. In contrast, heparin was inactive. The heparin analogue pentosan polysulfate (PPS), however, showed selective inhibition that was more than 2000-fold greater. The inhibitory effects of PPS on growth of SW-13/K-fgf cells, as well as endothelial cells, were fully reversible by an excess of added FGF. Daily intraperitoneal injections of PPS were tolerated well by athymic nude mice and prevented growth of subcutaneous SW-13/K-fgf tumor xenografts. PPS will be a useful tool to elucidate the effects of FGFs in vitro and in vivo and appears to be a prototype for the development of tumoricidal therapy based on targeting of growth factors.
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PMID:Tumor growth dependent on Kaposi's sarcoma-derived fibroblast growth factor inhibited by pentosan polysulfate. 170 34

The human hematopoietic progenitor cell antigen CD34 is synthesized and expressed by early normal hematopoietic progenitor cells and by many acute leukemias. Anti-CD34 antibodies also have been reported to stain blood vessels in tissue sections, and, more recently, CD34 mRNA has been detected in vascular endothelial cells. Therefore, the authors studied the diagnostic utility of immunohistochemical CD34 antigen detection in tumors of endothelial cell derivation and compared the results with stains for von Willebrand (vW) factor. A wide variety of epithelial and mesenchymal neoplasms also were examined to assess the specificity of CD34 for vascular neoplasia. Seven cases of angiosarcoma (seven of seven), five cases of Kaposi's sarcoma (five of five), and eight cases of epithelioid hemangioendothelioma (eight of eight) were moderately to strongly positive for CD34. This reactivity was equally intense in frozen sections, alcohol-fixed tissue, and formalin-fixed specimens. In many cases, the malignant endothelial cells stained more strongly than adjacent benign endothelium. Moreover, in most cases CD34 positivity was quantitatively and qualitatively stronger than staining for vW factor. Two cases of hemangiopericytoma (two of two) were CD34 positive but stained less intensely than the angiosarcomas, Kaposi's sarcomas, or hemangioendotheliomas. Five of six cases of hemangioma also stained positively for CD34; the nonreactive tumor in this group was the only one among 28 vascular neoplasms studied that was not reactive for CD34. In comparison, 9 of the 28 vascular tumors did not stain for vW factor. Three hundred fifty-seven tumors of nonvascular derivation also were examined for CD34 antigen expression. Focal light staining was seen in one pulmonary squamous cell carcinoma; moderate to intense staining was observed in half of the epithelioid sarcomas studied (8 of 16) and in a minority of leiomyosarcomas (3 of 22). These findings indicate that CD34 is a sensitive and relatively specific marker for neoplasms of vascular origin.
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PMID:The human hematopoietic progenitor cell antigen (CD34) in vascular neoplasia. 171 41

The histogenesis of Kaposi's sarcoma (KS) has been the subject of controversy, much of which has centered around whether the spindle cells of KS are derived from vascular endothelium or from lymphatics. Recently, some investigators have speculated that the spindle cells of KS are derived from dermal dendrocytes, a population of mononuclear dendritic cells normally present in the papillary and upper reticular dermis. These cells have been shown to proliferate in response to a variety of stimuli and have been reported to express the plasma proenzyme factor XIIIa. We examined immunohistochemically sections fixed in formaldehyde solution and embedded in paraffin from 20 tumor-stage, 15 patch-stage, and 15 plaque-stage lesions of KS with antibodies directed against factor XIIIa, factor VIII-related antigen, Ulex europaeus lectin, and LN3 (anti-HLA-DR) to investigate the relationship of dermal dendrocytes to KS in general and to try to clarify the histogenesis of this tumor. Our results revealed that the dermis of patch- and plaque-stage KS lesions contains an increased number of factor XIIIa-positive dermal dendrocytes compared with normal dermis and that some of these cells are spindle shaped. Many of the spindle cells in patch- and plaque-stage lesions of KS, however, are negative for factor XIIIa. The cells lining the slitlike spaces and some spindle-shaped cells in close proximity to the vascular spaces stain for factor VIII-related antigen and for Ulex europaeus lectin. LN3 labeled many cells resembling macrophages within the lesions and in papillary dermis. Less than 25% of the dendritic cells within the lesions and in the adjacent dermis expressed both factor XIIIa and LN3. Tumor-stage lesions showed focal but unequivocal staining of the spindle cells for factor VIII-related antigen and Ulex europaeus lectin. Tumor spindle cells were negative for factor XIIIa. Factor XIIIa-positive dendrocytes were plentiful in the uninvolved dermis and were aggregated around the periphery of the tumor nodules. The expression of factor VIII-related antigen and Ulex europaeus lectin by the spindle cells of nodular KS, and their lack of expression of factor XIIIa, suggests that the spindle-shaped tumor cells in all stages of KS are derived from endothelial cells and not from dermal dendrocytes. Dermal dendrocytes appear to undergo hyperplasia in response to KS of all stages. In patch- and early plaque-stage KS lesions, dermal dendrocytes are near factor VIII-related antigen-positive spindle cells and tumor vessels. The mechanism reactive dermal dendrocyte hyperplasia in KS remains obscure.
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PMID:Relationship of factor XIIIa-positive dermal dendrocytes to Kaposi's sarcoma. 171 58

The recombinant cytokines are increasingly important therapeutic agents for patients with AIDS. Recombinant interferon-alpha has demonstrated antitumor and antiretroviral activities in patients with Kaposi's sarcoma. Limited studies with interferon-beta suggest that it also has antitumor effects in patients with Kaposi's sarcoma, but interferon-gamma appears to be ineffective in controlling this tumor. The hematopoietic growth factors, including erythropoietin, granulocyte colony-stimulating factor (G-CSF), and granulocyte-macrophage colony-stimulating factor (GM-CSF), have been evaluated in several populations of human immunodeficiency virus (HIV)-infected individuals. The combination of G-CSF and recombinant human erythropoietin completely reversed the zidovudine-induced neutropenia of AIDS patients but was only partially effective in reversing anemia. In several clinical trials, GM-CSF induced marked increases in leukocyte counts and improved neutrophil function in some AIDS patients. In severely immunocompromised patients with disease caused by HIV who were receiving therapy with either G-CSF or GM-CSF, opportunistic infections continued to occur despite increases in circulating white blood cell counts. Recombinant cytokines may be used in the future in AIDS patients as adjunctive treatment with myelosuppressive antibiotics and chemotherapeutic drugs, as a possible means of enhancing host defense, or as agents of immune reconstitution.
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PMID:Use of recombinant interferons and hematopoietic growth factors in patients infected with human immunodeficiency virus. 196 13

Kaposi's sarcoma is an endothelial neoplasm with a variety of clinical presentations that rarely involve only the glans penis. Although it is recognized as a radiosensitive lesion, most of the reported cases of penile Kaposi's sarcoma have been treated surgically. We describe 2 otherwise healthy men with this unusual presentation of Kaposi's sarcoma who were treated with radiation therapy. These cases and a review of the literature demonstrate the role of radiation therapy in the conservative management of classic Kaposi's sarcoma involving the penis.
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PMID:Radiation therapy for classic Kaposi's sarcoma presenting only on the glans penis. 173 24

A careful overview of the classical appearances of Kaposi's sarcoma (KS) as well as of its variants were reviewed from the clinical and pathological point of view. The growth phases (stages) and the cellular patterns were histopathologically compared with emphasis on the developmental progression of disease as well as mitotic activity. Other morphological aspects were also assessed such as the features of the early phases and the incidence of hyaline bodies. One hundred and forty-three lesions from 96 patients mostly of the Italian sporadic type were investigated. A complete list of those entities which should be considered in differential diagnosis is shown and the dilemma of whether KS is a neoplasia or a hyperplasia is discussed.
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PMID:Kaposi's sarcoma: a clinico-pathologic overview. 174 49

A 56-year-old man presented with an inguinal lymph node enlargement. Histologic study of the tumor revealed three intermingled pathologic lesions: a nodular small cell lymphoma, an angiofollicular hyperplasia of vasculohyaline type, and a vascular neoplasia closely resembling Kaposi's sarcoma. The patient was immunocompetent and denied any homosexual relationships, transfusions, or drug use. The serum was negative for the presence of human immunodeficiency virus antibody. Computed tomographic scan and ultrasound examination revealed no other lymphadenopathies. This case shows that both hyperplastic and neoplastic lymphoid proliferations can occur simultaneously with vascular neoplasia. It thereby suggests that the neoplastic populations might interact to favor the tumor growth, the sequence and the nature of the stimulating events remaining unclear.
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PMID:Lymphadenopathic tumor exhibiting intermingled features of Kaposi's sarcoma, malignant lymphoma, and angiofollicular hyperplasia. 149 58

Spindle-shaped cells from Kaposi's sarcoma lesions (AIDS-KS cells) were cultured for long periods in the presence of conditioned medium from activated CD4-positive T cells (HTLV-II infected transformed nonvirus producer) and characterized under in vitro conditions. To investigate a possible vascular origin, AIDS-KS cells were analyzed for the presence of smooth muscle alpha-actin, a differentiation marker for vascular smooth muscle cells. Immunofluorescence studies using a monoclonal antibody for smooth muscle alpha-actin demonstrated positive staining of the AIDS-KS cells (KS-3 and KS-4) but not by endothelial cells or fibroblasts. Northern blot analysis using an oligonucleotide probe unique for human smooth muscle alpha-actin indicated the expression of this gene by AIDS-KS cells. Similar analysis of biopsies from the KS lesion showed that in addition to the staining of smooth muscle cells associated with the blood vessels, the tumor-related spindle cells also stained positively. These cells were also analyzed for the expression of different growth factor genes. The platelet-derived growth factor (PDGF) A-chain gene was expressed at a moderate level. The insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-2 (IGF-2) genes were not overexpressed in relation to control cells. These data suggest that the analyzed AIDS-KS cells may be smooth muscle-like cells and therefore of vascular origin. Based on these results as well as previous reports, we speculate that cells of the immune system may regulate growth of cells in the vascular wall by a novel pathway.
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PMID:AIDS-associated Kaposi's sarcoma-derived cells in long-term culture express and synthesize smooth muscle alpha-actin. 175 May 1

The epidemiology of the 3 types of Kaposi's sarcoma, the endothelial tumor that occurs in classic, African, and immunosuppressed forms, associated pathological factors, potential causative agents, and a tentative model to explain the condition are contained in this review. Kaposi's sarcoma as classically described usually occurs in the lower limbs of elderly men, often from Mediterranean heritage, and progresses slowly. African Kaposi's sarcoma attacks the lymphatic system and viscera of all ages with a short survival time. Immunosuppressed people, especially AIDS sufferers, get a rapidly progressive but treatable form, that will regress if the immunosuppressive drug is withdrawn. Kaposi's sarcoma preceded the AIDS epidemic in the U.S., and it is apparently waning in AIDS patients. Factors linked to Kaposi's sarcoma include male gender, the HLA-DR5 genetic marker, abuse of nitrite drugs, exposure to semen or anal sex, or to several viruses. Cytomegalovirus is the most prominent of many viruses considered as a potential causal agent. Since many patients are free of CMV, it is now thought to be only a circumstantial factor because it is epidemic in Africa, is transmitted sexually, and causes immunosuppression. Several hypothetical models have been proposed to explain the phenomenon of Kaposi's, notably the multiple cofactor model, and the avian hemangiotosis retrovirus model, for an undiscovered sexually/enterically transmitted virus. It is possible that a single yet unknown agent, probably an oncogenic virus, with several routes of transmission, varying individual susceptibility, increased virulence for immune suppressed hosts, long latent period, and increasing endemicity is the infectious agent for Kaposi's sarcoma.
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PMID:The epidemiology of classic, African, and immunosuppressed Kaposi's sarcoma. 176 11

Kaposi's Sarcoma (KS) is a tumor of multicentric origin, accounting for 4% of the observed neoplasia among organ transplant recipients. Its exact pathogenesis is still unknown. The diagnosis must be suspected in view of skin and/or subcutaneous tumor lesions with potential visceral involvement, which are easily confirmed by histological examination. Initial staging of the disease in 4 subgroups allows to guide therapy and prognosis. Therapeutic options depend on the transplanted organ and on results of early staging at time of diagnosis and treatment may associate: decrease and/or cessation of immunosuppression, laser therapy, radiotherapy and/or chemotherapy.
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PMID:[What position to take for Kaposi's sarcoma in organ transplantation?]. 176 33


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