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PubMedDate not supplied

Nephrectomy during operative management of retroperitoneal sarcoma.

BACKGROUND: Complete resection of a retroperitoneal sarcoma often requires removal of adjacent organs. In this study we evaluated the role of nephrectomy during operation for retroperitoneal sarcoma. METHODS: Between July 1982 and July 1995, 75 of the 371 (20%) patients who underwent resection of retroperitoneal sarcoma at MSKCC underwent concommitant nephrectomy. Data concerning the reasons for nephrectomy, degree of sarcomatous renal involvement, and survival were retrospectively analyzed. RESULTS: Fifty-four patients (72%) underwent nephrectomy during the initial resection, and 21 (28%) during a resection of a recurrent or persistent tumor. The most common reason for nephrectomy was total encasement by sarcoma (n = 40; 53%), followed by dense adherence of the tumor to the kidney (n = 21; 28%), and the direct invasion of the kidney by tumor (n = 2; 3%). Pathology demonstrated an absence of kidney invasion in the majority of cases (55 of 75; 73%). Renal capsular invasion was present in 11 of 75 (15%), renal parenchymal invasion in 7 of 75 (9%), and renal vein invasion in 2 of 75 (3%) of cases. There were no significant differences in survival based on degree of sarcoma involvement of the kidney, tumor grade, or whether the resection was for primary or recurrent disease. The 53 patients who underwent a complete gross resection of all tumor had a significantly improved long-term survival compared to the 20 patients who did not (50% versus 20% DFS at 5 years, respectively; p < 0.001). CONCLUSIONS: Decisions for concomitant nephrectomy during resection of retroperitoneal sarcoma should be based on whether this maneuver will provide a complete resection of all gross tumor, in which case the long-term disease-free survival of 50% is comparable to the reported 5-year survival of all patients with retroperitoneal sarcoma who are completely resected.

Adult↗
PubMed1983

Monophasic synovial sarcoma of spindle-cell type. Epithelial differentiation as revealed by ultrastructural features, content of prekeratin and binding of peanut agglutinin.

Monophasic synovial sarcomas of spindle-cell type and fibrosarcomas were studied by electron and immunofluorescence microscopy for their intermediate filament expression and the binding of peanut agglutinin (PNA). In monophasic synovial sarcomas of spindle-cell type (two cases), frequent cell-to-cell junctions, irregular cytoplasmic processes, and occasional cytoplasmic, tonofilament-like bundles of intermediate filaments were seen by electron microscopy. These features were absent from fibrosarcomas. Immunohistologically, the monophasic synovial sarcomas showed arrays of prekeratin-positive cells in the midst of the vimentin-positive spindle cells. By double fluorescence microscopy, the prekeratin-positive cells also bound PNA, like the epithelial-like cells of the classical biphasic synovial sarcoma. In contrast to monophasic synovial sarcomas, prekeratin-positive cells and arrays of PNA-binding cells, were not seen by immunofluorescence microscopy in fibrosarcomas (seven cases). Thus the prekeratin-content, the binding of PNA lectin, and certain ultrastructural features suggesting early epithelial differentiation, help to distinguish monophasic synovial sarcomas of spindle-cell type from other spindle cell sarcomas.

Adult↗
PubMed2004

[Therapy-induced tumor regression in adult soft tissue sarcomas-morphological findings].

Morphological findings of 21 soft tissue sarcomas of adulthood following preoperative chemo- and/or radiotherapy including perfusion therapy and resection are presented. The therapy-induced changes included a spectrum ranging from total tumor regression up to still completely vital tumor (median of all cases: 30% vital tumor tissue). 7 of 21 sarcomas (33%) were evaluated as responders (grade I-III). So-called malignant fibrous histiocytoma (MFH) revealed a good tumor response to preoperatively administered therapy (regression grades I and II). Myxoid/round-cell liposarcoma exhibited regression grades of IV-V (i.e. 30% up to 95% vital tumor tissue, non-responders). Synovial sarcoma was characterized by regression grades III up to VI (i.e. up to 100% vital tumor tissue without any signs of regression, 83% non-responders). Completely vital tumor was evident in 2 synovial sarcomas despite preoperative tumor therapy. These findings hint towards differences in response of distinct sarcoma entities to preoperative chemo-/radiotherapy. A grading of therapy-induced tumor regression in adult soft tissue sarcomas may best refer to already established grading schemes (e.g. according to the grading scheme for osteosarcomas following chemotherapy of Salzer-Kuntschik). A report of sarcoma resection specimens should include the percentage of vital tumor tissue.

Adult↗
PubMed2000

Patterns of keratin polypeptides in 110 biphasic, monophasic, and poorly differentiated synovial sarcomas.

Synovial sarcoma is a mesenchymal neoplasm of unknown histogenesis that shows various degrees of epithelial differentiation. It is known to contain simple epithelial keratins, and the possibility of complex epithelial keratin expression has been suggested. In this study, we immunohistochemically examined 110 well-documented synovial sarcomas including 44 biphasic, 48 monophasic, and 18 poorly differentiated (undifferentiated, highly mitotically active) tumors for 11 different keratin (K) polypeptides of the Moll catalogue. The epithelia of biphasic synovial sarcomas showed consistent, extensive reactivity for K7, K8, K14, K18, and K19. Other keratins seen in the epithelia of biphasic tumors included K17 (variable, in 77%), K13 (25%), K16 (23%), and K6 (24%) in the minority of biphasic tumors, predominantly in stratified-appearing epithelia. K10 was detected only focally in one case that showed keratinizing squamous differentiation. Focal expression of K20 was seen in 27% of cases. Monophasic synovial sarcomas had a more limited keratin repertory. Simple epithelial keratin positivity was detected, usually focally for K7 (79%), K19 (60%), K8 (45%), and K18 (46%). Two cases showed more extensive keratin positivity in the spindle cells. The monophasic tumors showed limited positivity for complex epithelial keratins: K14 (28%) and K17 (10%). K20 was detected focally in 6% of the monophasic tumors; other keratins were not detected. The poorly differentiated synovial sarcomas showed limited simple epithelial keratin reactivity, usually limited to scattered cells: K19 (61%), K7 (50%), K18 (47%), K8 (33%), but five cases showed more extensive positivity. Complex epithelial keratins were scant: K14 in one case and K17 in two cases. The immunoreactivity of capillary endothelia seen for K7 and K18 (but not for K8 and K19 with the antibodies used) is a potential diagnostic pitfall, and may cause overdiagnosis of synovial sarcoma if not properly recognized. In summary, we show complex patterns of keratins in synovial sarcoma, especially in the biphasic tumors. Such patterns establish a baseline in differential diagnostic considerations, and give an insight into the complex epithelial differentiation of this enigmatic mesenchymal tumor.

Adolescent↗
PubMed2005

Endoscopic resection for the diagnosis of visceral Kaposi's sarcoma.

Kaposi's sarcoma is an uncommon neoplasm that occasionally involves the gastrointestinal tract in immunosuppressed individuals. Infection with human herpes virus 8 is known to be necessary for developing all forms of Kaposi's sarcoma. We report a renal transplant recipient who developed visceral Kaposi's sarcoma 18 months after the transplantation. In Oriental countries, the incidence of Kaposi's sarcoma is extremely low, and this is the first case of Kaposi's sarcoma arising from a transplant recipient in Japan. Standard forceps biopsies of the gastric lesions failed to make the correct diagnosis. However, endoscopic resection successfully led to the correct diagnosis of Kaposi's sarcoma and herpes simplex virus 8 infection as well. This is the first report of a patient with visceral Kaposi's sarcoma who underwent endoscopic resection that reliably confirmed histological diagnosis and the viral genome at the same time.

Endoscopy, Digestive System↗
PubMed2005

Primary mediastinal lymph node malignancy with features suggestive of dendritic cell sarcoma.

A 56-year-old man underwent preoperative chest computed tomography to further evaluate a well defined mass in the middle lobe with subcarinal lymph node swelling. There was no pathological diagnosis established by either bronchoscopic biopsy specimens or computed tomography-guided percutaneous needle biopsy. The middle lobe and mediastinal lymph nodes were excised, then postoperative radiotherapy (60 Gy) was administered to the mediastinum. Results of histological and immunohistochemical study showed that the lung mass consisted of completely necrotic tissue and that the subcarinal lymph node was involved by malignant cells suggestive of dendritic cell sarcoma. Primary dendritic cell sarcoma of the mediastinal lymph node is extremely rare. Dendritic cell sarcoma is a neoplasm of reticular dendritic origin and includes both follicular dendritic cell sarcoma and interdigitating reticulum (or dendritic) cell sarcoma. These rare neoplasms may pose difficulty in pathologic diagnosis and treatment. Although our patient died of hepatic rupture due to dendritic cell sarcoma or gastric cancer metastases one year after surgery, complete surgical resection with or without postoperative radiotherapy may be an acceptable therapeutic option for localized dendritic cell sarcoma.

Dendritic Cells↗
PubMed1985

Analysis of T cell subsets in different clinical subgroups of patients with the acquired immune deficiency syndrome. Comparison with the "classic" form of Kaposi's sarcoma.

Ninety patients were grouped according to three different forms of acquired immune deficiency syndrome (AIDS): Kaposi's sarcoma "recent outbreak" type (38), reactive lymphadenopathy (27), and opportunistic infections (17), and a fourth group of patients with "classic" Kaposi's sarcoma (8). All patients with "classic" Kaposi's sarcoma were previously treated with electron-beam irradiation. These four groups were compared with 40 normal control subjects. Peripheral blood mononuclear cells isolated by density separation were reacted with a panel of mouse monoclonal antibodies that recognizes all peripheral blood T cells (OKT3-positive), helper (OKT4-positive), and suppressor (OKT8-positive) T cell subsets. The OKT4/OKT8 ratio was used to define the balance between these two subsets. All three groups with AIDS with or without Kaposi's sarcoma showed a decrease in the OKT4/OKT8 ratio. The group with "classic" Kaposi's sarcoma showed individual T cell subset values that were also abnormal. These findings confirm the previously reported imbalance of T cell subsets in patients with AIDS and Kaposi's sarcoma, which is also evident in patients with treated "classic" Kaposi's sarcoma.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Kaposi sarcoma presenting as a vulvar mass.

BACKGROUND: Kaposi sarcoma has become a common manifestation in people with AIDS, especially men. A few reports of Kaposi sarcoma in women with AIDS have involved nongenital areas. However, of the few patients with genital Kaposi sarcoma reported in the United States, none was believed to be human immunodeficiency virus (HIV)-positive. Genital Kaposi sarcoma associated with HIV has been reported in other parts of the world. CASE: A 29-year-old black woman presented with severe vulvar pain, vaginal discharge, and a vulvar mass. She had been diagnosed with AIDS 25 months earlier. Biopsy of the vulvar mass revealed Kaposi sarcoma; viral analysis of the tumor was positive for herpes simplex virus type 2. Sequencing of polymerase chain reaction product verified the presence of human papillomavirus 26. CONCLUSION: We report an HIV-associated Kaposi sarcoma presenting as a vulvar mass. This report should alert health care providers to include Kaposi sarcoma in the differential diagnosis of vulvar lesions.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Kaposi's sarcoma among persons with AIDS: a sexually transmitted infection?

In the United States Kaposi's sarcoma is at least 20,000 times more common in persons with acquired immunodeficiency syndrome (AIDS) than in the general population and 300 times more common than in other immunosuppressed groups. Among persons with the acquired immunodeficiency syndrome (AIDS) reported to Centers for Disease Control by March 31, 1989, 15% (13,616) had Kaposi's sarcoma. Kaposi's sarcoma was commoner among those who had acquired the human immunodeficiency virus (HIV) by sexual contact than parenterally, the percentage with Kaposi's sarcoma ranging from 1% in men with haemophilia to 21% in homosexual or bisexual men. Women were more likely to have Kaposi's sarcoma if their partners were bisexual men rather than intravenous drug users. Kaposi's sarcoma risk was not consistently related to age or race but varied across the United States, being greatest in the areas that were the initial foci of the AIDS epidemic. Thus Kaposi's sarcoma in persons with AIDS may be caused by an as yet unidentified infectious agent, transmitted mainly by sexual contact.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Clinical manifestations of classical, endemic African, and epidemic AIDS-associated Kaposi's sarcoma.

Kaposi's sarcoma, first described in 1972, is a rare, chronic neoplasm that occurs most often in elderly men of Eastern European origin. In the mid-twentieth century, more aggressive forms of Kaposi's sarcoma were found to be an endemic disease especially common among young black men in central Africa. Kaposi's sarcoma also occurs in iatrogenically immunosuppressed patients, such as kidney transplant recipients. In 1981, the sudden occurrence of an unusual, disseminated form of Kaposi's sarcoma in homosexual men in New York and California heralded the epidemic now known as the acquired immunodeficiency syndrome (AIDS). Ninety-five percent of all AIDS-associated Kaposi's sarcoma (AIDS-KS) has been in homosexual men; however, the incidence of AIDS-KS has diminished from greater than 40% of men with AIDS since 1981 to less than 20% in 1989. The remaining 5% of AIDS-KS has been seen in all other populations at risk for AIDS. The reasons for the remarkable persistent increased prevalence of AIDS-KS among homosexual men remains obscure. Clinically, AIDS-KS is a highly varied neoplastic disease characterized by multifocal mucocutaneous lesions often with lymphatic and visceral involvement. The etiology of Kaposi's sarcoma remains unknown although various hypotheses have been suggested, including endothelial-tumor growth factors, oncogenic expression, genetic predisposition, and environmental cofactors. An as-yet unidentified viruslike agent has been proposed as a possible direct cause of this neoplasm. Different treatment modalities for Kaposi's sarcoma have been employed with varying success, these include localized radiation therapy, cryotherapy, electrocauterization, surgical excision, and a variety of systemic chemotherapeutic regimens, as well as alpha-interferon. Although all available treatments help control the lesions, none lengthens survival.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Radiation induced sarcomas of bone following therapeutic radiation.

Because of new therapeutic trends of multi-modality and the importance of late effects, we have updated our series of radiation induced bone sarcomas seen at Memorial Sloan-Kettering Cancer Center over the past four decades. A total of 37 cases of bone sarcoma arising from normal bone in the irradiated field was analyzed. The median for latent period from irradiation to diagnosis of bone sarcoma was 11 years with a minimum latent period of four years. The median radiation dose for the bone sarcoma was 6000 rad in 6 weeks with a minimum total radiation dose of 3000 rad in 3 weeks. We have found nine patients who developed bone sarcomas in the radiation field after successful treatment of Hodgkin's disease. Criteria for radiation induced bone sarcomas and the magnitude of the risk of bone sarcomas are briefly discussed.

Bone Neoplasms↗
PubMed1984

Response of sarcomas of bone and of soft tissue to neutron beam therapy.

A total of 51 patients were treated at Fermilab for sarcoma of bone (25 patients) and soft tissue (26 patients). Neutrons were delivered in twice weekly fractions over 6-7 weeks to total doses between 18 and 26 Gy. Long-term local control (greater than 2 years) was achieved in 24 patients (47%). Overall local control rates were 44% in the bone sarcomas and 50% in the soft tissue tumors. Chondrosarcoma appeared relatively more responsive with 9 out of 16 (56%) controlled, compared to osteogenic sarcoma with 2 out of 9 (22%) controlled. Among the soft tissue tumors, liposarcoma (5/7 controlled) and neurogenic sarcoma (3/3 controlled) appear to be more responsive than other tumors. The overall survival rate was 40% in the entire series. These results are comparable with international experience in neutron therapy of sarcomas of bone and soft tissues. Out of 263 soft tissue sarcomas treated with neutrons only to full dosage throughout the world, 152 (58%) were locally controlled. Similarly out of 74 sarcomas of bone so treated, 44 (60%) were controlled.

Bone Neoplasms↗
PubMed1990

Results of multidisciplinary limb salvage in 240 consecutive bone sarcomas.

From 1979 to 1989, 240 bone sarcomas of limbs were treated by a multidisciplinary limb salvage protocol. The tumors included 112 osteosarcomas, 71 chondrosarcomas, 3 fibrosarcomas, 10 malignant histiocytofibromas, 40 Ewing's sarcomas and 4 other rarer sarcomas. Patients mean age was 28.6 yr (range 4-91 yr). The average tumor size was 13.5 cm (3-43 cm). There were 2 grade IA, 21 IB, 1 IIA, 188 IIB, and 28 III B according to Enneking's classification. Extratumoral en bloc resection was performed in all cases (large in 113, marginal in 121, intrafocal in 6) by the same surgeon. In poor responders to preoperative chemotherapy with Ewing's sarcomas or osteosarcomas, 35 Grays postoperative radiotherapy was administered. Ewing's sarcomas and osteosarcomas received short preoperative and long postoperative chemotherapy. At last follow-up (median 60 months, range 6-120 months), 150 patients were disease-free; 4 were under treatment and had visible disease; 86 had died. Actuarial disease-free survival rate for patients seen with localized previously untreated disease was 83% at 2 yr and 77% at 3 yr. Fifteen local recurrences were observed (6%). Statistical analysis confirmed the poor prognosis factors of visible metastasis, proximal location and large tumor size, and pointed out the major prognostic value of therapeutic factors: the effectiveness of chemotherapy in Ewing's sarcoma and osteosarcomas, and the adequacy of surgery in all cases. Limb salvage can be performed by a well experienced multidisciplinary team in 96% of limb sarcomas without major risk of local recurrence. However, amputation is safer if the surgeon lacks experience.

Adolescent↗
PubMed2004

Clinical outcomes of surgical resections for primary liver sarcoma in adults: results from a single centre.

BACKGROUND: Primary hepatic sarcoma is a rare tumour with a poor prognosis. METHODS: From 1997 to 2002 eight patients had liver resection for primary sarcoma of the liver at our institution. The clinical characteristics, imaging findings, surgical procedures, adjuvant therapy and outcome were retrospectively reviewed. There were two patients each with angiosarcoma (AS), leiomyosarcoma (LMS), and undifferentiated embryonal sarcoma (UES), one patient with epithelioid hemangioendothelioma (EHE) and one patient with malignant peripheral nerve sheath sarcoma (PNSS). RESULTS: The most common presenting symptoms were right upper quadrant pain and fever. Typical imaging findings were a heterogenous mass with poorly defined margins, pseudocapsule and aberrant vasculature. Preoperative diagnosis of a primary liver sarcoma was made in 7/8 cases, either by fine needle aspiration (n = 5) or angiography (n = 2). Five right hepatectomies and three trisegmentectomies were performed. An R (0) resection was possible in three cases. Two patients developed complications and there was one death. Adjuvant chemoradiotherapy was administered to 5/7 patients. Systemic chemotherapy led to tumour regression in both patients with UES which enabled a second hepatic resection. CONCLUSIONS: The majority of patients with primary liver sarcoma present with right upper quadrant pain, fever and a liver mass. Differentiating the rare primary liver sarcoma from the much more common hepatocellular carcinoma (HCC) may aid in planning therapy. Patients with resectable tumours should be referred for surgery. Liver resection combined with adjuvant chemotherapy are the mainstays of treatment for UES in the adult.

Adult↗
PubMed2004

Histopathological re-classification of extremity pleomorphic soft tissue sarcoma has clinical relevance.

AIMS: The aims were to describe the clinico-pathological features of 65 patients affected by soft tissue pleomorphic sarcomas of the extremities, to evaluate their clinical outcome and to explore the prognostic impact of clinical and pathologic parameters, on disease-free and overall survival. METHODS: Soft tissue pleomorphic sarcomas of the extremities were retrieved to be retrospectively re-evaluated in the current analysis. The following parameters were analysed: age, sex, site, size, stage, histotype, grade, surgical margins, therapy. Disease-free and overall survival rates were calculated according to the Kaplan-Meier method. A multivariate analysis was used to determine which variable had an independent effect on clinical outcome. RESULTS: Sixty-five patients with soft tissue pleomorphic sarcomas of the extremities were included in the study. Upon revision, there were 22 leiomyosarcomas, 13 myxofibrosarcomas, 9 liposarcomas, 10 pleomorphic MFH/undifferentiated high grade pleomorphic sarcomas, and 11 cases were other types of plemorphic sarcomas, including rhabdomyosarcoma (n=4), osteosarcoma (n=2), myofibrosarcoma (n=5). In the whole series, by multivariate analysis, stage was the only factor predictor of disease progression (p=0.001; RR 6.9; 95% CI 1.3-15.6). Considering only localized pleomorphic sarcomas the independent predictors of disease relapse were site (p=0.03; RR 3.6; 95% CI 1.0-12.4) and myogenic differentiation (p=0.04; RR 2.9; 95% CI 0.9-10.0), whereas myogenic differentiation resulted the only independent predictor of overall survival (p=0.03; RR 6.5; 95% CI 1.1-37.9). DISCUSSION: These results indicate that histopathological classification of soft tissue pleomorphic sarcomas is clinically relevant. In our experience, AJCC stage and myogenic differentiation are the factors which independently affect prognosis.

Adolescent↗
PubMed2004

Targeting of EWS/FLI-1 by RNA interference attenuates the tumor phenotype of Ewing's sarcoma cells in vitro.

The defining cytogenetic abnormality of Ewing's sarcoma is the presence of a balanced t(11;22) translocation expressing the EWS/FLI-1 chimeric fusion protein. The effect of EWS/FLI-1 appears to be dominant negative since over-expression of EWS does not overcome the sarcoma phenotype. Previous studies have shown that EWS/FLI-1 as well as related sarcoma fusion proteins are necessary and sufficient to induce transformation both in vitro and in vivo. In this study we report that synthetic small interfering RNA (siRNA) specifically suppresses EWS/FLI-1 fusion gene expression in SK-ES Ewing's sarcoma cells. Knockdown of the EWS/FLI-1 fusion protein is correlated with decreased cell proliferation and increased apoptosis. We demonstrate that Ewing's sarcoma tumors as well as Ewing's sarcoma cell lines predominantly express the CXCR4 chemokine receptor. Using an in vitro invasion assay, the SDF-1 ligand of CXCR4 was shown to be a potent stimulus of invasion by SK-ES cells. Knockdown of EWS/FLI-1 by RNA interference abrogates the invasiveness of SK-ES cells. These experiments suggest that targeted silencing of the EWS/FLI-1 fusion gene by siRNA represents a promising strategy to study the loss of EWS/FLI-1 protein in Ewing's sarcoma cells of otherwise identical genetic background.

Antineoplastic Agents↗
PubMed2004

Surveillance, epidemiology, and end results analysis of 2677 cases of uterine sarcoma 1989-1999.

OBJECTIVES: To determine the association of race with incidence, histology, treatment, and survival in women with uterine sarcoma during the period 1989-1999. METHODS: Uterine sarcomas were defined as leiomyosarcoma, carcinosarcoma, high-grade endometrial stromal sarcoma (HGESS), adenosarcoma, and sarcoma not otherwise specified (NOS). We used cases from Surveillance, Epidemiology, and End Results (SEER) program to compare uterine sarcoma among women >35 years of age. Using data from 1989 to 1999, we compared race-specific age-adjusted incidences, histological distributions, extent of disease at diagnosis, and race-specific survival. RESULTS: During the period of 1989-1999, 2677 women were diagnosed with uterine sarcoma, 2098 (78%) of whom were white and 420 (16%) of whom were black, and 159 (6%) of whom were of other races. The overall age-adjusted incidence for blacks was twice that of whites and more than twice that of women of other races (7/10(5) vs. 3.6/10(5) vs. 2.7/10(5), P < 0.0001). Racial differences in the incidence of uterine sarcoma existed for leiomyosarcoma (1.51/10(5) for blacks vs. 0.91/10(5) for whites, and 0.89 for women of other races, P < 0.01) and carcinosarcoma (4.3/10(5) for blacks, vs. 1.7/10(5) for whites, and 0.99 for women of other races, P < 0.001), but not for other histological types. Blacks with stage II disease were less likely to receive radiation in addition to surgery compared to whites (33% vs. 54%, P < 0.05). Five-year relative survival of patients with disease beyond the uterus was significantly longer for those that received radiation and surgery compared to those that received surgery alone. There were no racial differences in survival for women that received similar therapy. CONCLUSIONS: Adjuvant therapy improved survival for women with stage II-IV disease. Survival of black and white patients who received comparable treatment was similar.

Adult↗
PubMed2000

The metastatic ability of Ewing's sarcoma cells is modulated by stem cell factor and by its receptor c-kit.

Ewing's sarcoma is a primitive highly malignant tumor of bone and soft tissues usually metastasizing to bone, bone marrow, and lung. Growth factor receptors and their ligands may be involved in its growth and dissemination. We analyzed the expression of c-kit and its ligand stem cell factor (SCF) in a panel of six Ewing's sarcoma cell lines. All cell lines exhibited substantial levels of surface c-kit expression, and five of six displayed transmembrane SCF on the cell surface. Expression of c-kit was down-modulated in all lines by exposure to exogenous SCF. The SCF treatment was able to confer to cells a growth advantage in vitro, due both to an increase in cell proliferation and to a reduction in the apoptotic rate. When used in the lower compartment of a migration chamber, SCF acted as a strong chemoattractant for Ewing's sarcoma cells. The pretreatment of cells with SCF reduced their chemotactic response to SCF. In athymic nude mice, Ewing's sarcoma cells injected intravenously metastasized to the lung and to a variety of extrapulmonary sites, including bone and bone marrow. Metastatic sites resembled those observed in Ewing's sarcoma patients and corresponded to SCF-rich microenvironments. The in vitro pretreatment of cells with SCF strongly reduced the metastatic ability of Ewing's sarcoma cells, both to the lung and to extrapulmonary sites. This could be dependent on the down-modulation of c-kit expression observed in SCF-pretreated cells, leading to a reduced sensitivity to the chemotactic and proliferative actions of SCF. Our results indicate that the response to SCF mediated by c-kit may be involved in growth, migration, and metastatic ability of Ewing's sarcoma cells.

Animals↗