Morphological and cytogenetic studies of angiosarcoma in Stewart-Treves syndrome

Array CGH analysis identifies two distinct subgroups of primary angiosarcoma of bone

Molecular genetic studies on vascular tumors are rare. Recently, possible involvement of MYC and KDR has been documented in a subset of angiosarcomas of soft tissue. We performed a cytogenetic analysis of primary angiosarcomas of bone (n = 13) and soft tissue (n = 5) using high density array-comparative genomic hybridization (array-CGH). Regions of interest were validated by fluorescence in situ hybridization (FISH). Antibodies for candidate genes (SKI, MYC, KDR, and MAPK9) were selected and immunohistochemistry was performed. Six angiosarcomas of bone and four angiosarcomas of soft tissue showed chromosomal losses, gains, and high level amplifications. Cluster analysis identified two groups: a group with a complex genetic profile and a group with only few genetic aberrations. Five regions of interest were selected, which were located at chromosome bands 1p36.23, 2q32-34, 5q35, 8q24, and 17q21.32-24.2. Interphase FISH confirmed the high-level amplifications. Immunohistochemical analysis showed high expression of MYC (16/60), MAPK9 (63/69), and SKI (52/62). There were no differences between the two groups with regards to location, immunohistochemical expression nor survival. In summary, we identified two subgroups of angiosarcoma: those with few or no gross aberrations and those which show numerous genetic aberrations consisting of chromosomal losses, gains and high level amplifications or complex aberrations. The most common finding was amplification of 2q and 17q in both angiosarcoma of bone and soft tissue, suggesting overlap in tumorigenesis irrespective of their location. We show MYC amplification in primary angiosarcoma indicating this is not entirely specific for radiation-induced angiosarcoma.

Complex karyotype in a case of cutaneous lymphangiosarcoma associated with chronic lymphedema of the lower limb

Lymphangiosarcoma is a rare malignant neoplasm of endothelial cells. The term is used to describe an angiosarcoma associated with chronic lymphedema. The skin of the head and neck region is the most common site of origin. Rather few cytogenetic studies on lymphangiosarcoma are reported in the literature. We here describe a case of an 87-year-old woman, with a history of recurring lymphangitis and with an ulcerated nodular lesion of the leg. The histological diagnosis was a malignant neoplasm of vascular origin, with the morphological and immunohistochemical features of a lymphangiosarcoma. A series of antibodies (CD31, CD34, vimentin, podoplanin and HHV-8), conventional and molecular cytogenetic and Spectral Karyotyping (SKY-FISH) analyses were used to study this case. The immunohistochemical evaluation revealed that the neoplasm was positive for vimentin, CD31, CD34 and podoplanin and negative for HHV-8. The proliferation rate (Ki-67) was about 70%. Karyotype was defined using conventional cytogenetic and SKY-FISH. In addition, high-level of amplification was observed with MYC split signal probe. The morphological and immunohistochemical evaluations supported the diagnosis of lymphangiosarcoma. Moreover, the cytogenetic and molecular findings contributed towards accurately defining the karyotypic aberrations of this rare sarcoma.

Modeling human endothelial cell transformation in vascular neoplasias

Endothelial cell (EC)-derived neoplasias range from benign hemangioma to aggressive metastatic angiosarcoma, which responds poorly to current treatments and has a very high mortality rate. The development of treatments that are more effective for these disorders will be expedited by insight into the processes that promote abnormal proliferation and malignant transformation of human ECs. The study of primary endothelial malignancy has been limited by the rarity of the disease; however, there is potential for carefully characterized EC lines and animal models to play a central role in the discovery, development and testing of molecular targeted therapies for vascular neoplasias. This review describes molecular alterations that have been identified in EC-derived neoplasias, as well as the processes that underpin the immortalization and tumorigenic conversion of ECs. Human EC lines, established through the introduction of defined genetic elements or by culture of primary tumor tissue, are catalogued and discussed in relation to their relevance as models of vascular neoplasia.

Cutaneous angiosarcoma of the buttock complicated by severe thrombocytopenia: A case report

Angiosarcoma (AS) is an aggressive, malignant endothelial cell tumor of vascular or lymphatic origin, the presentation and clinical behavior of which may vary according to its location. This is the case report of a 56-year-old woman with cutaneous angiosarcoma (CAS) of the buttock complicated by severe thrombocytopenia. A review of the literature revealed that only nine cases of CAS with thrombocytopenia have been previously reported. The prognosis of CAS complicated by thrombocytopenia is poor, even after treatment with combined chemotherapy and radiotherapy (RT). The composite karyotype was 46,XX,t(12;20)(p13;p11.2)[3]/47,X,add(X)(q13),del(6)(q?),add(12)(p13),−21,+2mar[2]/45,XX,der(1)add(1)(p36.3)del(1)(q41),−20[1]/46,XX[13]. Only 13 cytogenetic cases of AS, including the present case, have been reported in the English literature thus far. In this case report, the clinical presentation and cytogenetic findings are described and the relevant literature on AS is reviewed.

Orotate phosphoribosyl transferase mRNA expression and the response of cholangiocarcinoma to 5-fluorouracil

AIM: To determine whether expression of certain enzymes related to 5-fluorouracil (5-FU) metabolism predicts 5-FU chemosensitivity in cholangiocarcinoma (CCA).

METHODS: The histoculture drug response assay (HDRA) was performed using surgically resected CCA tissues. Tumor cell viability was determined morphologically with hematoxylin and eosin- and terminal deoxynucleotide transferase-mediated dUTP nick-end labeling-stained tissues. The mRNA expression of thymidine phosphorylase (TP), orotate phosphoribosyl transferase (OPRT), thymidylate synthase (TS), and dihydropyrimidine dehydrogenase (DPD) was determined with real-time reverse transcriptase-polymerase chain reaction. The levels of gene expression and the sensitivity to 5-FU were evaluated.

RESULTS: Twenty-three CCA tissues were obtained from patients who had been diagnosed with intrahepatic CCA and who underwent surgical resection at Srinagarind Hospital, Khon Kaen University from 2007 to 2009. HDRA was used to determine the response of these CCA tissues to 5-FU. Based on the dose-response curve, 200 μg/mL 5-FU was selected as the test concentration. The percentage of inhibition index at the median point was selected as the cut-off point to differentiate the responding and non-responding tumors to 5-FU. When the relationship between TP, OPRT, TS and DPD mRNA expression levels and the sensitivity of CCA tissues to 5-FU was examined, only OPRT mRNA expression was significantly correlated with the response to 5-FU. The mean expression level of OPRT was significantly higher in the responder group compared to the non-responder group (0.41 ± 0.25 vs 0.22 ± 0.12, P < 0.05).

CONCLUSION: OPRT mRNA expression may be a useful predictor of 5-FU chemosensitivity of CCA. Whether OPRT mRNA could be used to predict the success of 5-FU chemotherapy in CCA patients requires confirmation in patients.

Alterations of the p53 and PIK3CA/AKT/mTOR pathways in angiosarcomas: a pattern distinct from other sarcomas with complex genomics

BACKGROUND

The p53 and phosphoinositide-3-kinase, catalytic, alpha polypeptide/v-akt murine thymoma viral oncogene homolog/mechanistic target of rapamycin (PIK3CA/AKT/mTOR) pathways frequently are altered in sarcoma with complex genomics, such as leiomyosarcoma (LMS) or undifferentiated pleomorphic sarcoma (UPS). The scale of genetic abnormalities in these pathways remains unknown in angiosarcoma (AS).

METHODS

The authors investigated the status of critical genes involved in the p53 and PIK3CA/AKT/mTOR pathways in a series of 62 AS.

RESULTS

The mutation and deletion rates of tumor protein 53 (TP53) were 4% and 0%, respectively. Overexpression of p53 was detected by immunohistochemistry in 49% of patients and was associated with inferior disease-free survival. Although p14 inactivation or overexpression of the human murine double minute homolog (HDM2) were frequent in LMS and UPS and could substitute for TP53 mutation or deletion, such alterations were rare in angiosarcomas. Phosphorylated ribosomal protein S6 kinase (p-S6K) and/or phosphorylated eukaryotic translation initiation factor 4E binding protein 1 (p-4eBP1) overexpression was observed in 42% of patients, suggesting frequent activation of the PIK3CA/AKT/mTOR pathway in angiosarcomas. Activation was not related to intragenic deletion of phosphatase and tensin homolog (PTEN), an aberration that is frequent in LMS and UPS but absent in angiosarcomas.

CONCLUSIONS

The current results indicated that angiosarcomas constitute a distinct subgroup among sarcomas with complex genomics. Although TP53 mutation and PTEN deletion are frequent in LMS and UPS, these aberrations are rarely involved in the pathogenesis of angiosarcoma.

Endothelial cell dysfunction and cytoskeletal changes associated with repression of p16(INK4a) during immortalization

The immortalization process is a fundamental step in the development of most (if not all) human cancers, including the aggressive endothelial cell (EC)-derived malignancy angiosarcoma. Inactivation of the tumor suppressor p16^INK4a and the development of multiple chromosomal abnormalities are features of angiosarcoma that are recapitulated during telomerase-mediated immortalization of human ECs in vitro. The present study used a panel of telomerase-immortalized bone marrow EC (BMEC) lines to define the consequences of inactivation of p16^INK4a on EC function and to identify molecular changes associated with repression of p16^INK4a. In a comparison of two immortalized BMEC mass cultures and six clones, the cell lines that repressed p16^INK4a showed a higher rate of proliferation and an impaired ability to undergo morphogenic differentiation and form vessel-like structures in vitro. Proteomic comparison of a p16^INK4a-negative and a p16^INK4a-positive BMEC mass culture at early- and late-passage time points following transduction with telomerase reverse transcriptase (hTERT) revealed altered expression of cytoskeletal proteins, including vimentin and α-tropomyosin (αTm), in the immortal cells. Immunoblot analyses of a panel of 11 immortal clones showed that cells that lacked p16^INK4a expression tended to accumulate more dramatic changes in these cytoskeletal proteins than cells that retained p16^INK4a expression. This corresponded with aberrant cytoskeletal architectures among p16^INK4a-negative clones, which featured thicker actin stress fibers and less fluid membrane ruffles than p16^INK4a-positive cells. A direct link between p16^INK4a repression and defective EC function was confirmed by analysis of normal cells transfected with small interfering RNA (siRNA) targeting p16^INK4a. siRNA-mediated repression of p16^INK4a significantly impaired random motility and vessel formation in vitro. This report is the first to demonstrate that ECs that repress the expression of p16^INK4a are prone to defects in motility, morphogenesis and cytoskeletal organization. These defects are likely to reflect alterations that occur during the development of EC-derived malignancies.

MYC high level gene amplification is a distinctive feature of angiosarcomas after irradiation or chronic lymphedema

Angiosarcomas (AS) are rare vascular malignancies that arise either de novo as primary tumors or secondary to irradiation or chronic lymphedema. The cytogenetics of angiosarcomas are poorly characterized. We applied array-comparative genomic hybridization as a screening method to identify recurrent alterations in 22 cases. Recurrent genetic alterations were identified only in secondary but not in primary AS. The most frequent recurrent alterations were high level amplifications on chromosome 8q24.21 (50%), followed by 10p12.33 (33%) and 5q35.3 (11%). Fluorescence in situ hybridization analysis in 28 primary and 33 secondary angiosarcomas (31 tumors secondary to irradiation, 2 tumors secondary to chronic lymphedema) confirmed high level amplification of MYC on chromosome 8q24.21 as a recurrent genetic alteration found exclusively in 55% of AS secondary to irradiation or chronic lymphedema, but not in primary AS. Amplification of MYC did not predispose to high grade morphology or increased cell turnover. In conclusion, despite their identical morphology, secondary AS are genetically different from primary AS and are characterized by a high frequency of high level amplifications of MYC. This finding may have implications both for the diagnosis and treatment of these tumors.

Comparative genomic hybridization in four angiosarcomas of the female breast

OBJECTIVE

Angiosarcomas represent a heterogeneous group of malignant vascular tumors occurring in different anatomic sites. In the female breast, they account for less than 1% of all malignant tumors and mainly develop as secondary angiosarcomas after prior irradiation. Data on cytogenetic findings in angiosarcomas are scarce and up to now no characteristic primary aberrations have been established. We herein add molecular cytogenetic findings in another 4 angiosarcomas to 11 previously reported cases.

METHODS

We investigated four angiosarcomas of the female breast (three primary angiosarcomas and one secondary tumor after irradiation for breast cancer) for DNA copy number changes using comparative genomic hybridization (CGH).

RESULTS

All angiosarcomas revealed aberrant karyotypes including multiple DNA copy number changes involving various chromosomes. Recurrent DNA copy number changes that occurred in at least two cases included gains at 1q, 7p, 7q, and 8q, as well as losses at 5q and 16q.

CONCLUSIONS

Angiosarcoma of the female breast represents a genetically heterogeneous tumor entity without a readily identifiable pattern of common chromosomal alterations. However, reviewing the cytogenetic literature on angiosarcomas of different sites, gains at 8q and 20p appear to emerge as the most frequent aberrations in at least a subset of these tumors.

Sinonasal angiosarcoma with marrow involvement at presentation mimicking malignant lymphoma: cytogenetic analysis using multiple techniques

Angiosarcoma of the head and neck most commonly involves the skin of the scalp or face; primary involvement of the sinonasal region is exceedingly rate. We report a patient with sinonasal angiosarcoma who showed marrow involvement at presentation. Marrow aspiration smears showed many large, often segregated blast-like cells, mimicking malignant lymphoma. However, trephine biopsy revealed formation of anastomosing vascular spaces by the tumor cells and immunoreactivity for CD31, supporting a diagnosis of angiosarcoma. DNA ploidy analysis showed an apparent diploidy. Nevertheless, conventional cytogenetics demonstrated very complex chromosomal abnormalities with the presence of multiple hypodiploid clones, together with several near-triploid to near-tetraploid clones showing structural abnormalities involving chromosomes 1, 3, 4, 9, 14, 16, 17, 18, and 22. The identification of these karyotypic changes has been facilitated by the application of comparative genomic hybridization and spectral karyotyping.

Splenic angiosarcoma: a clinicopathologic and immunophenotypic study of 28 cases

Primary angiosarcoma of the spleen is a rare neoplasm that has not been well characterized. We describe the clinical, morphologic, and immunophenotypic findings of 28 cases of primary splenic angiosarcoma, including one case that shares features of lymphangioma/lymphangiosarcoma. The patients included 16 men and 12 women, aged 29 to 85 years, with a mean of 59 years and median of 63 years. The majority of patients (75%) complained of abdominal pain, and 25% presented with splenic rupture. The most common physical finding was splenomegaly (71%). Seventeen of 21 patients were reported to have anemia. Macroscopic examination showed splenomegaly in 85% cases. Sectioning revealed discrete lesions in 88% of cases, ranging from well-circumscribed firm nodules to poorly delineated foci of necrosis and hemorrhage associated with cystic spaces. Microscopically, the tumors were heterogenous; however, all cases demonstrated at least a focal vasoformative component lined by atypical endothelial cells. Solid sarcomatous, papillary, and epithelioid growth patterns were observed. The solid sarcomatous component resembled fibrosarcoma in two cases and malignant fibroushistiocytoma in one case. Hemorrhage, necrosis, hemosiderin, extramedullary hematopoiesis, and intracytoplasmic hyaline globules were frequently identified. A panel of immunohistochemical studies revealed that the majority of tumors were immunoreactive for at least two markers of vascular differentiation (CD34, FVIIIRAg, VEGFR3, and CD31) and at least one marker of histiocytic differentiation (CD68 and/or lysozyme). Metastases developed in 100% of patients during the course of their disease. Twenty-six patients died of disease despite aggressive therapy, whereas only two patients are alive at last follow-up, one with disease at 8 years and the other without disease at 10 years. In conclusion, primary splenic angiosarcoma is an extremely aggressive neoplasm that is almost universally fatal. The majority of splenic angiosarcomas coexpress histiocytic and endothelial markers by immunohistochemical analysis, which suggest that some tumors may originate from splenic lining cells.

Intra-arterial mitoxantrone and paclitaxel in a patient with Stewart-Treves syndrome: selection of chemotherapy by an ex vivo ATP-based chemosensitivity assay

We report on a 72-year-old patient developing Stewart-Treves syndrome (STS) of the right arm 9 years after curative irradiation for ipsilateral stage III breast cancer. Facing the poor track record of both irradiation and chemotherapy in this highly malignant lymphangiosarcoma, amputation was recommended but refused by the patient. Therefore, limb conserving-therapy using three courses of intra-arterial mitoxantrone (MX) and paclitaxel (PTX) was attempted. This novel chemotherapy protocol was selected by pretherapeutic ex vivo ATP-based chemosensitivity testing of autologous tumor tissue. The patient experienced complete response, which was subsequent histologically confirmed by compartment resection. When developing recurrent STS outside of the perfused area 6 months after primary therapy, the patient was retested and reinduced with three other courses of intraarterial MX/PTX which again produced durable complete remission. This case demonstrates the benefit of indivdualized therapy in this prognostically desperate disease allowing both limb conservation and maintained quality of life.

Role of surgery in the management of postmastectomy extremity angiosarcoma (Stewart-Treves syndrome)

Stewart-Treves syndrome (STS) is the rare occurrence of angiosarcoma in a setting of postmastectomy upper extremity lymphedema. A collective comparison of outcomes following various initial treatment options in STS has not previously been reported. We reviewed 160 cases of STS reported in the literature since 1966. We analyzed the relationship between initial treatment and survival in all 92 of these patients for whom detailed treatment and outcome data had been reported. There was no significant difference in survival comparing those initially treated with wide excision (n = 16) and those treated with amputation (n = 45) (P = 0.40). Even in the setting of initial surgical treatment, overall long-term survival was poor (<40%). There have been even fewer long-term survivors among those treated initially with regional chemotherapy (n = 7) or radiation therapy (n = 24). An update on STS and a discussion of recent advances in the understanding of its molecular pathogenesis that may result in future treatment improvements are presented.

Derivation of a new hematopoietic cell line with endothelial features from a patient with transformed myeloproliferative syndrome: a case report

BACKGROUND

During embryonal development primitive hematopoiesis can be observed first in the yolk sac, in which both hematopoietic and endothelial cells are derived from a common precursor, the hemangioblast. Whether cells with this dual differentiation potential persist during postnatal life is unknown.

METHODS

A cell line was derived from a patient with secondary acute leukemia. Because of its ability to grow in soft agar and in SCID mice, this cell line was analyzed for expression of differentiation antigens by fluorescence-activated cell sorter analysis, immunocytochemistry, fluorescent in situ hybridization (FISH) analysis with simultaneous cell surface staining, and polymerase chain reaction (PCR).

RESULTS

A new cell line was established from a patient with essential thrombocytosis that transformed into acute leukemia. The patient's initial clinical presentation included skin and lymph node infiltrations that were taken for an angiosarcoma due to positivity for CD34, CD31, and von Willebrand factor on immunohistology. In addition to hematopoietic markers, leukemic cells expressed endothelial antigens such as CD62E, CD105, and bound Ulex europäeus lectin-1. Immunocytochemistry revealed positive staining for vascular endothelial growth factor receptor type 2 (KDR), Tie-2/Tek, the angiopoietin receptor, and vascular endothelial cadherin. These results were confirmed by PCR analysis. Simultaneous staining for CD62E and FISH analysis showed that cells with endothelial characteristics belonged to the leukemia. FISH analysis of histologic sections of the lymph node infiltration confirmed this manifestation as part of the leukemic process. The derived cell line, UKE-1, forms colonies in soft agar and is tumorigenic in SCID mice.

CONCLUSIONS

This new cell line, UKE-1, appears to combine hematopoietic and endothelial features, indicating the close ontogenic relation of both lineages.

Angiosarcoma: current review

Angiosarcoma (AS) is a rare malignant tumor of the skin and soft tissues. Due to this lesions's histopathologic similarity to other soft tissue and skin neoplasms, several names had been previously used to describe AS. In the following article, we present a comprehensive review of the literature and prior studies pertaining to AS. The purpose of this article is to provide the reader with a better understanding of the causative factors, clinical findings, and histological features of this uncommon but potentially lethal tumor. Furthermore, we discuss present therapeutic options and outcomes as well as summarize recent advances in AS tumor biology and cytogenetics.

Angiosarcomas express mixed endothelial phenotypes of blood and lymphatic capillaries: podoplanin as a specific marker for lymphatic endothelium

Angiosarcomas apparently derive from blood vessel endothelial cells; however, occasionally their histological features suggest mixed origin from blood and lymphatic endothelia. In the absence of specific positive markers for lymphatic endothelia the precise distinction between these components has not been possible. Here we provide evidence by light and electron microscopic immunohistochemistry that podoplanin, a approximately 38-kd membrane glycoprotein of podocytes, is specifically expressed in the endothelium of lymphatic capillaries, but not in the blood vasculature. In normal skin and kidney, podoplanin colocalized with vascular endothelial growth factor receptor-3, the only other lymphatic marker presently available. Complementary immunostaining of blood vessels was obtained with established endothelial markers (CD31, CD34, factor VIII-related antigen, and Ulex europaeus I lectin) as well as podocalyxin, another podocytic protein that is also localized in endothelia of blood vessels. Podoplanin specifically immunolabeled endothelia of benign tumorous lesions of undisputed lymphatic origin (lymphangiomas, hygromas) and was detected there as a 38-kd protein by immunoblotting. As paradigms of malignant vascular tumors, poorly differentiated (G3) common angiosarcomas (n = 8), epitheloid angiosarcomas (n = 3), and intestinal Kaposi's sarcomas (n = 5) were examined for their podoplanin content in relation to conventional endothelial markers. The relative number of tumor cells expressing podoplanin was estimated and, although the number of cases in this preliminary study was limited to 16, an apparent spectrum of podoplanin expression emerged that can be divided into a low-expression group in which 0-10% of tumor cells contained podoplanin, a moderate-expression group with 30-60% and a high-expression group with 70-100%. Ten of eleven angiosarcomas and all Kaposi's sarcomas showed mixed expression of both lymphatic and blood vascular endothelial phenotypes. By double labeling, most podoplanin-positive tumor cells coexpressed endothelial markers of blood vessels, whereas few tumor cells were positive for individual markers only. From these results we conclude that (1) podoplanin is a selective marker of lymphatic endothelium; (2) G3 angiosarcomas display a quantitative spectrum of podoplanin-expressing tumor cells; (3) in most angiosarcomas, a varying subset of tumor cells coexpresses podoplanin and endothelial markers of blood vessels; and (4) all endothelial cells of Kaposi's sarcomas expressed the lymphatic marker podoplanin.

Angiosarcomas express mixed endothelial phenotypes of blood and lymphatic capillaries: podoplanin as a specific marker for lymphatic endothelium

Angiosarcomas apparently derive from blood vessel endothelial cells; however, occasionally their histological features suggest mixed origin from blood and lymphatic endothelia. In the absence of specific positive markers for lymphatic endothelia the precise distinction between these components has not been possible. Here we provide evidence by light and electron microscopic immunohistochemistry that podoplanin, a approximately 38-kd membrane glycoprotein of podocytes, is specifically expressed in the endothelium of lymphatic capillaries, but not in the blood vasculature. In normal skin and kidney, podoplanin colocalized with vascular endothelial growth factor receptor-3, the only other lymphatic marker presently available. Complementary immunostaining of blood vessels was obtained with established endothelial markers (CD31, CD34, factor VIII-related antigen, and Ulex europaeus I lectin) as well as podocalyxin, another podocytic protein that is also localized in endothelia of blood vessels. Podoplanin specifically immunolabeled endothelia of benign tumorous lesions of undisputed lymphatic origin (lymphangiomas, hygromas) and was detected there as a 38-kd protein by immunoblotting. As paradigms of malignant vascular tumors, poorly differentiated (G3) common angiosarcomas (n = 8), epitheloid angiosarcomas (n = 3), and intestinal Kaposi's sarcomas (n = 5) were examined for their podoplanin content in relation to conventional endothelial markers. The relative number of tumor cells expressing podoplanin was estimated and, although the number of cases in this preliminary study was limited to 16, an apparent spectrum of podoplanin expression emerged that can be divided into a low-expression group in which 0-10% of tumor cells contained podoplanin, a moderate-expression group with 30-60% and a high-expression group with 70-100%. Ten of eleven angiosarcomas and all Kaposi's sarcomas showed mixed expression of both lymphatic and blood vascular endothelial phenotypes. By double labeling, most podoplanin-positive tumor cells coexpressed endothelial markers of blood vessels, whereas few tumor cells were positive for individual markers only. From these results we conclude that (1) podoplanin is a selective marker of lymphatic endothelium; (2) G3 angiosarcomas display a quantitative spectrum of podoplanin-expressing tumor cells; (3) in most angiosarcomas, a varying subset of tumor cells coexpresses podoplanin and endothelial markers of blood vessels; and (4) all endothelial cells of Kaposi's sarcomas expressed the lymphatic marker podoplanin.

Thymidine phosphorylase, 2-deoxy-D-ribose and angiogenesis

Angiogenesis is the term used to describe the formation of new blood vessels from the existing vasculature. In order to attract new vessels, a tissue must release an endothelial-cell chemoattractant. 2-Deoxy-D-ribose is produced in vivo by the catalytic action of thymidine phosphorylase (TP) on thymidine and has recently been identified as an endothelial-cell chemoattractant and angiogenesis-inducing factor. TP, previously known only for its role in nucleotide salvage, is now known to be angiogenic. TP expression is elevated in many solid tumours and in chronically inflamed tissues, both known areas of active angiogenesis. There is evidence that TP is also involved in physiological angiogenesis such as endometrial angiogenesis during the menstrual cycle. The majority of known endothelial-cell chemoattractants are polypeptides that bind to endothelial-cell-surface receptors. In contrast, 2-deoxy-D-ribose appears to lack a cell-surface receptor. Glucose is another sugar that acts as an endothelial-cell chemoattractant. The migratory activity of glucose is blocked by ouabain. It is possible that 2-deoxy-D-ribose and glucose stimulate endothelial-cell migration via a similar mechanistic pathway.

Cytogenetic analysis of four angiosarcomas from deep and superficial soft tissue

Angiosarcomas are rare malignant vascular tumors, most commonly found in the skin or superficial soft tissue. We found clonal chromosome aberrations in four short-term cultured angiosarcomas. Two cases were diagnosed as epithelioid angiosarcomas, and one as postmastectomy angiosarcoma. Two of the tumors were deep-seated and two were superficial. Angiosarcomas from deep, soft tissue are extremely rare and have never been cytogenetically investigated before. The chromosome number ranged from hypodiploid to hypertriploid. When the results from the present study were combined with data on the four previously reported cytogenetically aberrant angiosarcomas, the most frequently rearranged chromosomes were 5, 7, 8, 13, 15, 20, 22, and the Y chromosome. Recurrent changes, each found in three of these eight angiosarcomas, were gains of 5pter-p11, 8p12-qter, and 20pter-q12, losses of 7pter-p15 and 22q13-qter, and -Y in two of three men.