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Comparison of cell surface antigen HBA71 (p30/32MIC2), neuron-specific enolase, and vimentin in the immunohistochemical analysis of Ewing's sarcoma of bone.

The HBA71 antigen is an M(r) 30,000/32,000 cell surface glycoprotein (p30/32MIC2), encoded by the pseudoautosomal MIC2 gene on chromosomes X and Y, that is expressed in Ewing's sarcomas. Immunohistochemical studies demonstrate a striking specificity for HBA71 among neoplasms of diverse histologic types. In the present study, 43 cases of Ewing's sarcoma of bone were tested for HBA71 expression and six additional immunohistochemical markers regularly used in the differential diagnosis of small round-cell tumors of childhood and adolescence (neuron-specific enolase, vimentin, leukocyte common antigen, cytokeratins, muscle-specific actin, desmin). The study design included (a) random selection of Ewing's sarcoma cases from the files of Memorial Hospital beginning in 1968, (b) blind review of the original histopathologic diagnoses of ES, (c) side-by-side immunohistochemical study of recut histologic specimens, and (d) statistical analysis of immunohistochemical findings in view of clinical outcome. Of the seven antigens studied, only HBA71, neuron-specific enolase and vimentin were expressed in a significant proportion of cases. Forty-one of the 43 cases were HBA71+ (95% sensitivity); of these, 21 were neuron-specific enolase+, 29 were vimentin+, and 15 were both neuron-specific enolase+ and vimentin+. One tumor lacked all antigens, and one was vimentin+ only. Comparison of tumor tissues in five patients obtained before and after cytostatic chemotherapy showed no change in HBA71 expression or in the other antigens tested. Product-limit survival analysis (median disease-free survival was 27.3 months for the study cohort) revealed no significance of neuron-specific enolase or vimentin marker status. These results raise doubts about the usefulness of neuron-specific enolase and vimentin immunohistochemistry to distinguish Ewing's sarcoma from other small round-cell tumors of childhood and adolescence or as prognostic indicators in Ewing's sarcoma. The positive identification of Ewing's sarcoma of bone now becomes a reality using HBA71 immunohistochemistry, either as a sole method or in combination with chromosomal breakpoint analysis. This may result in achieving uniform diagnostic criteria for evaluating the biologic, therapeutic, and prognostic aspects of Ewing's sarcoma and related neoplasms.

Adolescent↗

Herbimycin A inhibits the association of p60v-src with the cytoskeletal structure and with phosphatidylinositol 3' kinase.

To search for the biochemical prerequisites for morphological transformation by p60v-src, we examined the effect of herbimycin A, a potent inhibitor of cell transformation, on chicken embryonic fibroblasts transformed by Rous sarcoma virus. A small dose of herbimycin (0.1-0.3 micrograms ml-1) was enough to convert the cell morphology to a normal phenotype with a concomitant reassembly of microfilament bundles. In the cells treated with the drug, the majority of the substrates for p60v-src remained phosphorylated and p60v-src was myristylated, membrane associated and fairly active as a protein kinase. Under the same conditions, however, the association of p60v-src with the cytoskeletal structure and with phosphatidylinositol 3' kinase was strongly inhibited, suggesting that the interactions of p60v-src with the cellular structure and the enzyme were indispensable for morphological transformation.

Animals↗

Trisomy 8 in primary esthesioneuroblastoma.

Esthesioneuroblastoma is a rare malignancy believed to be derived from neuroectodermal stem cells within the olfactory epithelium. We have obtained the karyotype of a primary esthesioneuroblastoma following brief (7-day) in vitro culture, and have determined that the only observable cytogenetic anomaly is the presence of an additional chromosome 8. Previously, the karyotypes of two cell lines established from metastatic esthesioneuroblastomas have been reported to contain the equivalent of three copies of chromosome 8, in addition to other chromosomal aberrations, including the reciprocal translocation, t(11;22)(q24;q12). Examination of the cytogenetic literature suggests that an extra copy of chromosome 8 is a common occurrence in undifferentiated small round cell tumors frequently observed to carry the t(11;22), including esthesioneuroblastoma, Ewing's sarcoma, peripheral neuroepithelioma, Askin's tumor, and rhabdomyosarcoma. These data, combined with our report of a small round cell tumor with the karyotype 47,XY, +8, indicate that trisomy 8 may be a common phenomenon in these tumors, and may also provide some sort of selective advantage to these tumor types.

Chromosome Aberrations↗

The IGF-I receptor gene promoter is a molecular target for the Ewing's sarcoma-Wilms' tumor 1 fusion protein.

Desmoplastic small round cell tumor (DSRCT) is an abdominal malignancy in children which is characterized by a recurrent chromosomal translocation, t(11;22)(p13;q12). This rearrangement results in the fusion of the ubiquitously expressed EWS1 gene to the Wilms' tumor suppressor (WT1) gene. The chimeric protein contains the N-terminal domain of EWS1 fused to the DNA-binding domain of WT1, including zinc fingers 2-4. Because WT1 has been shown previously to bind and repress the insulin-like growth factor I (IGF-I-R) promoter, we investigated whether this promoter is, in addition, a target for the aberrant EWS/WT1 transcription factor. EWS/WT1 activated the IGF-I-R promoter approximately 340%, whereas a fusion protein containing a three-amino acid insert (KTS) between zinc fingers 3 and 4 had no effect. On the other hand, expression vectors encoding either WT1 or EWS1 reduced the activity of the promoter to 46 and 58% of control values, respectively. Results of gel shift assays indicate that the binding affinity of EWS/WT1 to a fragment of the 5'-flanking region of the receptor promoter was higher than the affinity of WT1 itself. Consistent with the results of functional assays, the binding of EWS/WT1(+KTS) was significantly reduced. Due to the central role of the IGF-I-R in tumorigenesis, activation of the receptor promoter by EWS/WT1 may constitute a potential mechanism for the etiology and/or progression of DSRCT.

Base Sequence↗

Immunohistochemistry of small round-cell tumors.

The term "small round-cell tumor" describes a group of highly aggressive malignant tumors composed of relatively small and monotonous undifferentiated cells with high nuclear to cytoplasmic ratios. This group includes Ewing's sarcoma (ES), peripheral neuroepithelioma (aka, primitive neuroectodermal tumor or extraskeletal ES), peripheral neuroblastoma ("classic-type"), rhabdomyosarcoma, desmoplastic small round-cell tumor, lymphoma, leukemia, small-cell osteosarcoma, small-cell carcinoma (either undifferentiated or neuroendocrine), olfactory neuroblastoma, cutaneous neuroendocrine carcinoma (aka, Merkel-cell carcinoma), small-cell melanoma, and mesenchymal chondrosarcoma. Their clinical presentations often overlap, thus making a definitive diagnosis problematic in some cases. Yet, a clear understanding of their clinicopathologic features usually allows for a confident diagnosis, especially if immunohistochemistry is used. The following is a review of the immunohistochemistry of this small round-cell tumor group.

Biomarkers, Tumor↗

Molecular heterogeneity and function of EWS-WT1 fusion transcripts in desmoplastic small round cell tumors.

Desmoplastic small round cell tumor (DSRCT) is a primitive sarcoma with a consistent cytogenetic abnormality, t(11;22)(p13;q12). This chromosomal translocation generates a chimeric transcript that is formed by fusion of the 5' region of the Ewing's sarcoma gene, EWS, with the 3' DNA-binding segment of WT1, the Wilms' tumor suppressor gene. We collected 14 DSRCT tumor samples and examined the hybrid transcripts. We identified: (a) combinatorial heterogeneity of EWS exons fused to WT1 including use of EWS exons 7, 8, and 9; (b) subpopulations of variant transcripts in 6 of 14 tumors characterized by aberrant splicing resulting in loss of EWS exon 6 or WT1 exon 9; (c) multiple cDNA products with large internal deletions; and (d) insertion of small stretches of heterologous DNA at the fusion site or exon splice region in transcripts from two tumors. Most of the splice variants were in-frame, and in vitro translated fusion proteins with intact DNA-binding motifs formed complexes with a WT1 response element in gel mobility assays. Each of the chimeric proteins retains the ability to bind to the GC and TC elements of the early transcription factor EGR-1 as well as WT1 consensus sequences. We present evidence that various EWS-WT1 proteins up-regulated EGR-1 promoter activity and that this up-regulation is specifically dependent upon the absence of the exon 9 KTS domain of WT1. The molecular diversity and functionality exhibited by these fusion transcripts may have significant biological implications for their transactivating and tumorigenic potential.

Abdominal Neoplasms↗

Translocation of chromosomes 11 and 22 in choroidal metastatic Ewing sarcoma detected by fluorescent in situ hybridization.

PURPOSE: To describe a patient with metastasis of Ewing sarcoma to the choroid and the molecular genetics of the tumor. METHODS: A 26-year-old woman with metastatic Ewing sarcoma developed large choroidal masses in the left eye and died 2 months later. Autopsy of the eyes was performed. Dual-color fluorescent in situ hybridization was used to detect genetic alteration in the ocular tumor with EWS and FLI-1 probes. RESULTS: Histopathology confirmed choroidal metastatic Ewing sarcoma. Molecular analysis showed chromosomal translocation t(11;22)(q24;q12) or EWS/FLI-1 rearrangement in the malignant cells of the eye. CONCLUSIONS: Ewing sarcoma can rarely metastasize to the uvea. Molecular detection of the t(11;22)(q24;q12) translocation in Ewing sarcoma is valuable in the differential diagnosis of small round cell tumors.

Adult↗

Gastrointestinal stromal tumors: differential diagnosis.

Availability of KIT tyrosine kinase inhibitors for specific treatment of GISTs has magnified the importance of accurate differential diagnosis of GIST from other tumors occurring in the GI tract and abdomen. The general problems in this distinction include histological mimicry of other mesenchymal tumors with GIST, occasional KIT-negativity of GIST, and KIT-positivity of non-GISTs. Up to 5% to 10% gastric GISTs and <2% of intestinal GISTs can be KIT-negative. The identification of these tumors as GISTs is based on knowledge of the spectrum of GIST morphology, and can be supported by molecular diagnosis of KIT and PDGFRA mutations (the latter pertain to gastric tumors). True smooth muscle tumors (rare in GI tract except in esophagus and colon) can be separated from GISTs by the eosinophilic tinctorial quality of tumor cells, positivity for smooth muscle markers, and negativity for KIT. Desmoids can form large GIST-like masses, but are composed of spindled or stellate-shaped cells in a densely collagenous stroma. Negativity for KIT and nuclear positivity for beta-catenin are differentiating features. GI schwannomas, melanoma, and rare primary clear cell sarcoma are S100-positive, usually with characteristic histology. The latter two can be KIT-positive. KIT-positive non-GISTs include some sarcomas, especially angiosarcoma and Ewing sarcoma, extramedullary myeloid tumor, seminoma, and a few carcinomas, notably small cell carcinoma of lung. Spurious KIT-positivity, seen with some polyclonal KIT antibodies, has been a source of confusion leading to probable false-positive results in fibroblastic tumors and occasional other sarcomas, such as leiomyosarcomas. Integration of histological features with carefully standardized immunohistochemistry, supported by KIT and PDGFRA mutation analysis, is the cornerstone of state-of-the art differential diagnosis of GIST. To comprehensively capture all GISTs, KIT immunostains should be performed on all unclassified epithelioid and mesenchymal tumors of the abdomen. This is a US government work. There are no restrictions on its use.

Diagnosis, Differential↗

Clear cell sarcoma of soft tissues. Mayo Clinic experience with 35 cases.

Thirty-five cases of clear cell sarcoma of soft tissues were studied to determine the clinical or morphologic features that are important in predicting prognosis. Tumors occurred most commonly in the extremities, and the majority of the patients were young women. Surgery was the elected treatment in every case. Five patients experienced local recurrences, and metastases developed in 22. Fifty-four percent of the patients died of tumor, 11% are alive with disease, and the remaining 34% are alive and well; the average survival for each group was 67 months, 113 months, and 103.5 months, respectively. This sarcoma is characterized by small clusters of polygonal to spindle cells featuring clear to slightly basophilic cytoplasm and vesicular nuclei with prominent nucleoli. The clusters are separated by delicate fibrous septa. In a deletion, clear cell sarcoma has low mitotic activity, little or no necrosis, and mild nuclear pleomorphism. Tumor size and the presence of necrosis are statistically significant predictors of prognosis. All 12 patients with tumors measuring > 5 cm died of disease or are alive with disease. Eleven of the 20 patients with tumors measuring < 5 cm are alive with no evidence of disease. Tumor necrosis was present in 10 cases; eight of these patients died of disease and one is alive with disseminated metastases.

Adolescent↗

The EWS gene, involved in Ewing family of tumors, malignant melanoma of soft parts and desmoplastic small round cell tumors, codes for an RNA binding protein with novel regulatory domains.

The EWS gene, which maps to band q12 of human chromosome 22, is involved in a wide variety of human solid tumors including Ewing sarcoma, related primitive neuroectodermal tumors, malignant melanoma of soft parts and desmoplastic small round cell tumors. In these tumors, the EWS is fused to genes encoding transcriptional activators/repressors, like Fli-1 or erg or ATF 1 or wt1. To better understand the function of the EWS protein, we cloned the EWS cDNA. Sequence analysis of this cDNA revealed differential splicing involving two exons encoding 72 amino acids. Both alternatively spliced transcripts, EWS and EWS-b, are expressed in a variety of cells. Because EWS proteins contain putative conserved RNA binding motifs, we studied the RNA binding properties of the EWS protein. The EWS-b protein binds to RNA in vitro and, specifically, to poly G and poly U. The RNA binding activity was localized to the carboxy terminal 86 amino acids, which constitute RGG box. Thus the amino terminal domain of EWS (NTD-EWS), which is involved in chromosome translocation may regulate the specificity of RNA binding activity of EWS. An EWS-erg chimeric protein, which is found in Ewing's sarcoma cells, functions as a transcriptional activator. Mutational analysis of EWS-erg chimeric protein revealed that NTD-EWS functions as a regulatory domain for the transcriptional activation properties of EWS-erg chimeric protein.

Amino Acid Sequence↗

Chest wall tumors in infancy and childhood.

The chest wall is an infrequent site of malignancy in infancy and childhood. Management of these tumors, however, is of particular concern because of their aggressive behavior and the functional impairment which may result from local treatment. From 1976 to 1987 we have treated seventeen infants and children with tumors of the chest wall. Askin's tumors and Ewing's sarcoma were considered as a single entity, malignant small round cell tumor (MSRCT), and account for the majority (11 of the 17 patients). Other tumors represented were infantile fibrosarcoma (1), undifferentiated spindle cell sarcomas (2), osteogenic sarcoma (1), large cell lymphoma (1), and synovial sarcoma (1). Nine of 17 patients have survived (median follow-up of survivors 5 years); six patients died of disease and two from complications of therapy. All four patients with MSRCT and metastasis at diagnosis died of disease despite chemotherapy and radiotherapy. Four of the seven patients with localized MSRCT, who received combined modality therapy including resection (two after initial chemotherapy), radiotherapy, and chemotherapy, were continuously disease-free 16 months to 10 years following diagnosis. One of the three patients who failed died of complications of surgery to her extensive primary. A second patient had a relapse of disease in a hilar node four years after finishing vincristine, actinomycin, and cytoxan (VAC) chemotherapy; she was retreated with Adriamycin (doxorubicin, Adria Laboratories, Columbus, Ohio), vincristine, and cyclophosphamide as well as radiotherapy to her hilum and remains in second remission 56 months following her recurrence. The third patient suffered a distant relapse in bone and, before succumbing to his MSRCT, developed acute monocytic leukemia and died during a remission induction attempt. Mixed results were obtained for the patients with other tumor types.

Adolescent↗

[18F]FLT PET for diagnosis and staging of thoracic tumours.

The nucleoside analogue 3'-deoxy-3'-[18F]fluorothymidine (FLT) has been introduced for imaging of tumour cell proliferation by positron emission tomography (PET). This study evaluated the use of FLT in patients with thoracic tumours prior to treatment. Whole-body FLT PET was performed in 16 patients with 18 tumours [17 thoracic tumours (nine non-small cell lung cancers, five oesophageal carcinomas, two sarcomas, one Hodgkin's lymphoma) and one renal carcinoma] before treatment. Fluorine-18 fluorodeoxyglucose (FDG) PET was performed for comparison except in those patients with oesophageal carcinoma. For semi-quantitative analysis, the average and maximum standardised uptake values (avgSUV and maxSUV, respectively) (FLT, 114+/-20 min p.i.; FDG, 87+/-8 min p.i.; 50% isocontour region of interest) was calculated. All 17 thoracic tumours and 19/20 metastases revealed significant FLT accumulation, resulting in easy delineation from surrounding tissue. The additional small grade 1 renal carcinoma was not detected with either FLT or FDG. In most lung tumours (avgSUV 1.5-8.2) and metastases, FLT showed intense uptake. However, one of two spinal bone metastases was missed owing to the high physiological FLT uptake in the surrounding bone marrow. Oesophageal carcinoma primaries (avgSUV 2.7-10.0) and occasional metastases showed particularly favourable tumour/non-tumour contrast. Compared with FDG, tumour uptake of FLT was lower (avgSUV, P=0.0006; maxSUV, P=0.0001), with a significant linear correlation (avgSUV, r2=0.45; maxSUV, r2=0.49) between FLT and FDG. It is concluded that FLT PET accurately visualises thoracic tumour lesions. In the liver and the bone marrow, high physiological FLT uptake hampers detection of metastases. On the other hand, FLT may be favourable for imaging of brain metastases owing to the low physiological uptake.

Adult↗

Catecholamine fluorescence and tissue culture morphology. Technics in the diagnosis of neuroblastoma.

Neuroblastoma is often confused histologically with other small round cell tumors such as Ewing's sarcoma, acute lymphocytic leukemia, lymphoma, and oat cell carcinoma, particularly at metastatic sites. Studies were performed to evaluate glyoxylic acid-induced catecholamine fluorescence as a rapid method for identifying neuroblastoma cells in biopsy specimens. The morphology of tumor explants in tissue culture was also evaluated for use as a diagnostic aid. Eighteen neuroblastomas were stained for catecholamines; 78% showed specific catecholamine fluorescence. Two ganglioneurons and a pheochromocytoma also showed positive catecholamine fluorescence. All 20 neuroblastomas placed in tissue culture demonstrated neurite outgrowth, a property that distinguishes neuroblastoma from other small round cell neoplasms. Seventeen nonneuroblastoma tumors displayed neither specific fluorescence nor neurite outgrowth. The ability of these two technics to identify neuroblastoma was compared with routine histology, urinary vanillylmandelic acid (VMA) spot tests, quantitative urinary VMA and catecholamine assays, and electron microscopy. Only electron microscopy was as sensitive as fluorescence and morphology in culture. The fluorescence method is rapid and simple and provides a valuable tumor marker when positive. Neurite outgrowth in cell culture and electron microscopy, although more time-consuming, were the most sensitive of all the diagnostic methods evaluated.

Adult↗

Application of a panel of antiganglioside monoclonal antibodies to cytologic specimens.

The cytologic evaluation of poorly differentiated tumors frequently poses a diagnostic dilemma as to the tissue of origin. To assess the diagnostic utility of monoclonal antibodies (MAbs) in these situations, we applied a panel of three highly purified MAbs specific for tumor-associated ganglioside epitopes to a diverse series of cytologic specimens. The panel was composed of DMAb-3, reactive with the epitope GalNAc beta 1-4 (NeuAc alpha 2-3)Gal- of GM2; DMAb-7, reactive with the epitope (NeuAc alpha 2-8NeuAc alpha 2-3)Gal beta 1-4(Glc or GlcNAc)- of GD3 and 3'8'-LD1; and DMAb-20, reactive with the epitope GalNAc beta 1-4(NeuAc alpha 2-8NeuAc alpha 2-3)Gal- of GD2. The cytologic material consisted of air-dried Cytospin preparations prepared predominantly from fine needle aspirates and stained with the ABC immunohistochemical method. Positive reactivity was recognized when greater than 5% of tumor cells stained with the antibody; lesser reactivity was called negative. DMAb-3 stained 9/14 (64%) glial tumors, 4/13 (31%) nonglial central nervous system tumors, 1/21 (5%) melanomas, 7/38 (18%) non-small cell carcinomas (NSCC), 1/15 (7%) small cell carcinomas (SCC), 0/9 (0%) lymphomas/leukemias, 2/10 (20%) sarcomas, 1/7 (14%) miscellaneous tumors and 2/2 (100%) reactive fluids. DMAb-7 recognized 14/14 (100%) glial tumors, 9/13 (69%) non-glial central nervous system tumors, 19/22 (86%) melanomas, 19/43 (44%) NSCC, 5/15 (33%) SCC, 2/9 (22%) lymphomas/leukemias, 6/10 (60%) sarcomas, 1/7 (14%) miscellaneous tumors and 4/4 (100%) reactive fluids. DMAb-20 stained 6/14 (43%) glial tumors, 2/13 (15%) nonglial central nervous system tumors, 1/21 (5%) melanomas, 4/38 (10%) NSCC, 0/15 (0%) SCC, 0/9 (0%) lymphomas/leukemias, 1/10 (10%) sarcomas, 1/7 (14%) miscellaneous tumors and 1/3 (33%) reactive fluids. The GD3-reactive DMAb-7 recognized a large portion of many tumor types and thus is not diagnostically useful alone. DMAb-3 and DMAb-20 were more selective and showed the strongest reactivity for glial tumors and minimal reactivity for melanomas, small cell carcinomas, and lymphomas or leukemias. DMAb-3 and DMAb-20 may be useful as components of a larger panel of MAbs in distinguishing between poorly differentiated tumors in samples derived from the central nervous system.

Antibodies, Monoclonal↗

[Paraneoplastic cerebellar degeneration as initial presentation of a pancreatic small-cell carcinoma].

INTRODUCTION: Oat (small) cell carcinoma is the type of tumour most frequently associated to neurologic paraneoplastic syndromes. It is usually located in the lungs although it has been described in some other locations. Cerebellar symptoms may appear alone, associated to anti Yo antibodies ( Breast and gynaecologic carcinomas), or as manifestation of a more generalized paraneoplastic encephalopathy, associated to signs and symptoms of some other neurologic systems affected. CASE REPORT: A 52 year old patient consulted due to a pancerebellar clinical picture, which started about two months before, and later associated to polineuropathy. Abdominal CT showed a 4 cm mass in the head of the pancreas. Pathologic evaluation demonstrated a poorly differentiated small cell pancreatic tumour. Anti Hu antibodies in high titres were found both in serum and cerebrospinal fluid. DISCUSSION: The association of anti Hu immunity and paraneoplastic encephalomyelitis has been observed in patients with neuroblastoma, seminomas, colorectal, breast and prostate carcinomas and some types of sarcoma. Only about 1% of pancreatic malignancies correspond to small cell type. We have not found any previous report about the association between a paraneoplastic syndrome and pancreatic poorly differentiated small cell carcinoma.

Antibodies↗

[Cooperative Ewing's Sarcoma Studies 81/86: pathologico-anatomic and immunohistochemical findings and differential diagnosis of Ewing sarcoma].

158 cases of the Cooperative Ewing's Sarcoma Trials (CESS 81/86), which have been documented at the Pediatric Tumor Registry, Kiel, were studied by conventional light microscopy and immunohistochemistry. There were 77 cases of typical Ewing's sarcoma with 70 cases being located in the skeleton and 7 in soft tissues. Of the 14 cases of atypical Ewing's sarcoma 7 cases each were localized in bone and in soft tissue, respectively. In contrast to typical Ewing's sarcoma, cells of atypical Ewing's sarcoma were larger and displayed more heterochromatin. Both, typical and atypical Ewing's sarcoma reacted positively for vimentin. Other stains were negative, notably the neuron specific enolase (NSE). In 55 cases a diagnosis of malignant peripheral neuroectodermal tumor (MPNT) was made. Histologically most of these tumors resembled atypical Ewing's sarcoma. By immunohistochemistry positive reactions were found for NSE, vimentin, protein S-100, neurofilaments and glial fibrillary acidic protein. In 3 cases a diagnosis of small cell osteosarcoma was made. There were 2 cases of undifferentiated sarcoma of bone, 2 cases of soft tissue sarcoma of undetermined histogenesis and 2 cases of rhabdomyosarcoma. Of the 4 tumors which could be investigated for response to polychemotherapy, 1 each corresponded to grade II and III, respectively, and 2 to grade IV according to the classification of histologic grade of regression established by Salzer-Kuntschik et al. (1983).

Adolescent↗

Spontaneous cell shedding by tumor cells in monolayer culture.

Sarcoma 180 monolayers spontaneously shed single cells and small multicellular aggregates into the surrounding medium to produce a dual population of floating and substratum-attached cells. Shedding was a motility-associated event that occurred when cells attempted to migrate over one another. It resulted from a combination of cell shape change and active motility, which increased sensitivity to fluid shear dislodgement by reducing a cell's surface area of adhesive contact and increasing strain tension at its adhesive contact points. Shedding occurred at all phases of the cell cycle. Extracellular matrix but not conditioned medium enhanced the floating subpopulation by slowing the kinetics of reattachment to plastic and cellular substrate. Although sarcoma 180 cells are anchorage independent in the sense that they grow readily in single cell suspension, they nevertheless exhibited anchorage modulation of their cell cycle. Short periods in suspension produced a mild G1 accumulation, whereas longer periods of anchorage deprivation led to a mild G2 accumulation which appeared to result from an interference with cytokinesis.

Animals↗

Ewing's sarcoma. Cytologic features in fine needle aspirates in two cases.

The cytologic findings of two cases of Ewing's sarcoma in fine needle aspiration biopsies are presented in relation to the subsequent histologic findings. The malignant cells were arranged in monocellular layers, pseudorosettes and in perivascular palisades in a fibrillar background. The nuclei were monomorphous with small nucleoli and finely granular chromatin. These features may be helpful in distinguishing this tumor from other small-cell neoplasms; the differential diagnosis between Ewing's sarcoma and such tumors is discussed.

Adolescent↗