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At least 271 records · Page 15Linked to original sources

Intercellular junctions in Ewing sarcoma/primitive neuroectodermal tumor: additional evidence of epithelial differentiation.

Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) has recently been shown to frequently express cytokeratins, suggesting partial epithelial differentiation. Older ultrastructural studies have documented primitive cell-cell junctions in ES/PNET, reportedly resembling poorly formed desmosomes. Recently, paraffin-reactive antibodies have become available to proteins found in a variety of intercellular junctions indicative of epithelial differentiation, including tight junctions, desmosomes and adherens junctions. We examined intercellular junction protein expression in a large number of genetically confirmed ES/PNET. Formalin-fixed, paraffin-embedded sections from 23 primary and seven recurrent or metastatic cases of genetically confirmed ES/PNET were immunostained for claudin-1 and occludin (tight junction structural proteins), zonula occludens-1 (ZO-1, tight junction linker protein), desmoglein 1/2 (desmosomal adherens protein), desmoplakin (desmosomal structural protein) and E-cadherin (epithelial adherens junction protein), using steam heat-induced epitope retrieval and the Dako Envision system. Cases with >5% positive cells were scored as 'positive'. Normal colonic epithelium and skin served as external positive controls. Claudin-1 was expressed by 19 of 30 specimens (63%), ZO-1 was expressed by 15 of 29 specimens (51%), and occludin was expressed by three of 28 specimens (11%). In 28 specimens all three tight junction markers were evaluable. In all, 15 samples (54%) expressed only one tight junction marker, and 10 samples (36%) expressed two tight junction markers. No case expressed all three tight junction markers. Desmoglein was expressed in one of 30 (3%) samples. Desmoplakin was expressed in two of 28 (7%) samples. E-cadherin was negative in all cases. Our data suggest that many of the previously described cell-cell junctions in ES/PNET are poorly formed tight junctions, given the high frequency of claudin-1 and ZO-1 expression. This may underestimate the true frequency of tight junction protein expression in ES/PNET, as there are at least 20 different claudins and other ZO proteins. These tight junctions are almost certainly abnormal, given the absence of occludin expression in most cases. Desmosomal and adherens junction protein expression was rare to absent. Our findings provide additional evidence that ES/PNET frequently show partial epithelial differentiation.

Bone Neoplasms↗

Melanotic neuroectodermal tumor of infancy.

The lack of knowledge regarding the histogenesis of the melanotic neuroectodermal tumor of infancy may account for the numerous names given to this neoplasm. The most appropriate nomenclature is melanotic neuroectodermal tumor of infancy as this term is both clinically descriptive and reflects its most likely histogenesis. The histological diagnosis of this neoplasm and its known benign biological behavior should be appreciated so that radical surgery or radiotherapy is not undertaken. Our case report includes an electron microscopic analysis which is in keeping with other reported cases. We have not confirmed high urinary VMA levels prior to resection of the lesion.

Female↗

Melanotic neuroectodermal tumor of infancy. MR findings and a review of the literature.

Melanotic neuroectodermal tumor of infancy is an uncommon neoplasm occurring primarily in the child one year or less in age. Difficulty in deciding the cellular origin of this tumor has led to numerous names, including congenital melanocarcinoma, melanotic epithelial odontoma, melanotic ameloblastoma, and retinal anlage tumor, to list a few. Electron microscopy and histochemical studies, however, have now established the neural crest as the most likely origin. The most frequent site of occurrence is the maxilla followed by the skull, the brain and the mandible. The genital organs are the most frequent extracranial site. Within the skull, there is a predilection for the anterior fontanel. The following is a case report of a young child with melanotic neuroectodermal tumor of infancy arising at the anterior fontanel. Included is a discussion of magnetic resonance (MR) findings, which to our knowledge, have not been previously reported in this tumor.

Female↗

Primitive neuroectodermal tumor of the cervix: a clinicopathologic and immunohistochemical study of two cases.

Two cases of primary primitive neuroectodermal tumors of the cervix are presented. The two female patients are 35 and 51 years of age who presented with abnormal uterine bleeding of several weeks' duration. On gynecologic examination, a mass in the cervical area was palpated and a biopsy was obtained. The initial biopsy was interpreted as possible small cell carcinoma in both women. A radical hysterectomy was performed in both patients. Grossly, in both cases, the uterine cervix showed an ill-defined tumor involving the ectocervix and endocervix, measuring 3.0 and 4.0 cm in greatest dimension, respectively, and showing areas of necrosis and hemorrhage. Histologic sections showed the presence of a malignant neoplasm arranged in cords and with a vague nesting pattern. Areas of hemorrhage and necrosis were also present. The neoplastic cells were characterized by having indistinct cell borders, small round to oval nuclei, and inconspicuous nucleoli. Mitotic figures were easily identified. In one patient, the tumor had metastasized to lymph nodes. Immunohistochemical studies revealed the neoplastic cells to be positive for antibodies for CD99 and focally for synaptophysin, while keratin, chromogranin, smooth muscle actin, desmin, and neurofilament protein were negative. Both patients received adjuvant chemotherapy and remain alive 5 and 18 months after initial diagnosis, respectively. The present cases highlight the importance of keeping primitive neuroectodermal tumors in the differential diagnosis of small cell neoplasms of the uterine cervix.

Adult↗

A general aspect on soft-tissue sarcoma and c-kit expression in primitive neuroectodermal tumor and Ewing's sarcoma. Is there any role in disease process?

OBJECTIVE: Within soft-tissue sarcoma, primitive neuroectodermal tumors have been shown to cover a wide spectrum of small round cell sarcomas, including Ewing's sarcomas (ES) and primitive neuroectodermal tumors (PNET). The role of the stem cell factor/kit pathway has been investigated in different human tumors especially in chronic myelocytic leukemia and gastrointestinal stromal tumor and an autocrine loop has been assumed in small cell lung carcinoma, and recently in ES and PNET. Our aim is to investigate the c-kit expression in ES and PNET and also to assessed if c-kit has any role in disease process. METHODS: We thoroughly searched the archives of the Department of Pathology, Faculty of Medicine, Cukurova University Turkey, between 2000 and 2004; and found 14 ES and 14 PNET paraffin embedded tissues. We carried out the detection of the c-kit expression by immunohistochemical staining. RESULTS: The patient's median age was 23.7 +/-14.6 (12 male and 16 female). Five were diagnosed as metastatic disease whereas 23 were diagnosed as non-metastatic disease at admission. The mean follow up period was 38.9 +/- 22.3 months. The main localization of the disease was lower extremity (32.1%), and others were as follows: head and neck 25%, thorax and abdomen 14.3%, pelvic and upper extremity 7.1% (11 were localized skeletal and 17 were extraskeletal). According to treatment modalities, 10 were treated with surgery alone, 11 with surgery and chemotherapy, and 7 with surgery, radiation therapy and also with chemotherapy. The primary tumor was lower than 5 cm in its dimension in 21 patients. While in 5 patients, tumor was more than 5 cm but did not exceed 10 cm, it was >10 cm in 2 patients. The c-kit expression was positive in 7 patients both cytoplasmic and membranously, whereas 8 patients were positive cytoplasmically. In 5 PNET patients, c-kit expression were stained immunohistochemically in over 50% and in 3 of ES patients. There was no significant correlation between c-kit expression and gender, localization, metastatic status, treatment modalities and tumor. Although in survival analysis, patients treated with surgery alone lived longer, while >50% of patients treated with c-kit expression lived for a shorter period. CONCLUSION: We suggest that therapy with tyrosine kinase inhibitor for PNET and ES patients may be an alternative in addition to standard therapy modalities, especially in patients non-responsive to standard therapy.

Adolescent↗

Primitive neuroectodermal tumor of the uterus: a case report and review of literature.

A case of primitive neuroectodermal tumor arising in the uterine corpus of a 43-year-old woman is presented. The tumor mass was 13.3 cm and extended to the uterine serosa, endocervical stroma, and left adnexa. Histologically, the tumor was composed of small blue cells with scant cytoplasm, indistinct cell borders, hyperchromatic round nuclei, and inconspicuous nucleoli focally forming pseudorosettes, suggestive of neuroectodermal origin. The tumor cells displayed strong immunoreactivity for CD99 and FLI1. Cytogenetic fluorescence in situ hybridization study revealed presence of an EWS-FLI1 fusion gene. To the best of our knowledge, this is the first case of primitive neuroectodermal tumor of the uterus with diagnosis confirmed by FLI1 immunohistochemical labeling and demonstration of t (11; 22) by fluorescence in situ hybridization.

12E7 Antigen↗

Peripheral primitive neuroectodermal tumor involving the paravertebral and retroperitoneal regions.

A rare case of peripheral primitive neuroectodermal tumor (PNET) is reported. A 68-year-old woman complaining of lumbago was admitted to our hospital. Diagnosis was made based on pathological findings characterized by Homer Wright-type rosettes. Ultrastructural examination showed the presence of neurosecretory granules and short cytoplasmic processes, which were highly suggestive of neural differentiation. Chromosomal analysis of the neoplastic cells revealed translocation (11;22)(q24;q12), which is often found in Ewing's sarcoma and Askin tumor. These results strengthen the hypothesis of a common histogenesis for these small round cell tumors, and suggest common oncogenesis for these neoplasms.

Aged↗

PTEN and DMBT1 homozygous deletion and expression in medulloblastomas and supratentorial primitive neuroectodermal tumors.

Medulloblastoma, which accounts for 20-25% of all childhood brain tumors, is defined as a primitive neuroectodermal tumor (PNET) located in the cerebellum. Supratentorial PNET are less frequent than medulloblastoma. But their clinical outcome is worse than in medulloblastomas. Chromosome 10q contains at least 2 tumor suppressor genes that might play a role in brain tumor development: PTEN and DMBT1. The aim of this study was to compare the status of homozygous deletion and expression of PTEN and DMBT1 genes in PNET primary tumor samples and cell lines. Homozygous deletions of PTEN and DMBT1 were studied in 32 paraffin-embedded PNET samples (23 medulloblastomas and 9 supratentorial PNET) and in 7 PNET cell lines, by differential PCR and by FISH. PTEN homozygous losses were demonstrated in 7 medulloblastomas (32%) and in no supratentorial PNET, while homozygous deletions of DMBT1 appeared in 1 supratentorial PNET (20%) and in 7 medulloblastomas (33%). No homozygous deletion of PTEN or DMBT1 was detected in any of the PNET cell lines either by differential PCR or by FISH. Expression study of the 2 genes was performed in the 7 PNET cell lines by RT-PCR. One PNET cell line lacked PTEN and DMBT1 expression, while 2 medulloblastoma cell lines did not express DMBT1. Our results add some positive data to the hypothesis that supratentorial PNETs and medulloblastomas might be genetically different.

Agglutinins↗

Modulation of a novel thermolysin-like metallo-endopeptidase activity during retinoic acid-induced differentiation of human neuroectodermal tumor cell lines.

Neuroectodermal tumours express hormones which are post-translationally processed and inactivated by the action of specific proteases and peptidases. The data reported here show the presence of a novel thermolysin-like metallo-endopeptidase activity in several human cell lines. The soluble fractions of neuroblastoma, melanoma and a glioblastoma tumour cell lines are able, with different degrees, to cleave the Ser12-Phe13 bond of a DVDERDVRGFAS decreases FLNH2 substrate. The inhibition pattern suggests a metallo-endopeptidase thermolysin-like character, with the involvement of thiol group(s), clearly distinct from neutral endopeptidase (NEP; EC 3.4.24.11). This metallo-endopeptidase activity is down regulated during retinoic acid(RA)-induced neuronal differentiation in the RA-sensitive SK-N-BE(2) cells but not in the RA-resistant BE(2)-M17 cells, suggesting that the down regulation is related to neuronal differentiation and not a direct effect of RA on the enzymatic activity.

Amino Acid Sequence↗

A primitive neuroectodermal tumor on the face: case report.

In 1918, Stout defined the lesion in which small round cells originating from the ulnar nerve formed a rosette as neuroepithelioma. It was claimed that this tumor originated from neuroectodermis and was different from the classical neuroblastoma. The term primitive neuroectodermal tumor (PNET) involves a group of tumors of the soft tissue originating from neural crest and resulting from the brain, spinal cord and branches of the sympathetic nervous system. Extracranial primitive neuroectodermal tumors originate from neural crest cells outside the sympathetic and central nervous system. PNET also has some distinctive histological, immunohistochemical and ultrastructural features. It is usually encountered in children and young adults; most frequently located in thoracopulmonary region (Askin's tumor). The second most commonly involved body part is the extremities. It is very rarely located on the face. PNET is an aggressive tumor. In fact, the disease has a rapid progression, causes local or distant metastases and 50% of the patients die within two years of the presentation. It is treated with aggressive surgery as well as chemotherapy and radiotherapy. In this report, we presented a case of PNET located on the right cheek with multiple distant metastases. Clinicians should be on alert when treating facial tumors, not to skip PNET, which is a very aggressive one.

Aged↗

Experimental production of primitive neuroectodermal tumors and its relevance to human neuro-oncology.

The origin and nature of central nervous system tumors primarily composed of primitive neuroepithelial cells have intrigued neuropathologists since 1925, when the prototype tumor in this group, the medulloblastoma, was defined as a specific type by Bailey and Cushing. Theories regarding this group of tumors have been widely divergent, ranging from classification as sarcomas, neuroblastomas, spongioblastomas, ie, poorly differentiated gliomas (including astrocytic, oligodendroglial, and ependymal), to primitive tumors with a capacity for multidirectional differentiation. Studies of both human and experimental primitive neuroectodermal tumors have yielded considerable information about biological features, although controversies remain regarding interpretation of the findings. Moreover, many investigators remain fixed upon the notion that discovery of the "cell of origin" of these tumors will somehow enhance understanding of their nature. Rationale for relevance of this view is examined against the current state of knowledge regarding carcinogenesis as a whole and studies of human and experimental primitive neuroectodermal tumors in particular, and it is concluded that the time has come to discard the archaic concept of cell of origin and devote resources to investigations of the phenotypic character of the tumor and its relationship to prognosis and treatment.

Animals↗

Differential spectrum of expression of neural cell adhesion molecule isoforms and L1 adhesion molecules on human neuroectodermal tumors.

A series of four medulloblastomas, seven neuroblastomas (Nb), two ependymomas, and three gliomas, human neuroectodermal tumors, were screened for their expression of adhesion molecules L1, carcinoembryonic antigen, neural cell adhesion molecule isoforms (N-CAM) and HNK1 epitope by Western blotting and double immunofluorescence labeling. All seven neuroblastomas, whatever their differentiated state, expressed L1, a neural cell surface developmental antigen, whereas all other tumors tested were negative. All tumors expressed N-CAM; however, a large diversity was observed among the isoforms. Low sialylated N-CAM 140 was present, with different intensity, in ependymomas and astrocytomas. High sialylated isoforms were detected by a monoclonal antibody (anti-MenB) specifically recognizing high polymers of alpha 2-8 linked neuraminic acid. They were expressed in all medulloblastomas studied (4 of 4), and in 4 of 7 Nbs examined. Negative cases corresponded to tumors having undergone chemotherapeutic treatment or to ganglioneuroma. The interconversion from high to low sialylated forms might reflect changes which are critical for the conversion of Nbs into benign ganglioneuromas. HNK1 epitope was expressed on a large diversity of molecules by nearly all tumors except two Nbs which were also negative with anti-MenB antibody. This simultaneous loss of carbohydrate epitopes could correlate with higher maturation states of the tumors. None of the tumors expressed carcinoembryonic antigen. Therefore, anti-L1 and anti-MenB antibodies define differentiation-related antigens that could differentiate between Nbs and other tumors and may prove helpful in diagnosis and understanding of the biological nature of neuroectodermal tumors. An immunodot assay was set up and allowed to titrate the presence of polysialic acid units in cerebrospinal fluid from patients presenting meningeal spread of medulloblastomas. It could help to assess metastasis and to monitor the effects of chemotherapeutic treatment on polysialylated N-CAM positive tumors.

Adult↗

Heritable formation of neuroectodermal tumor in transgenic mice carrying the combined E1 region gene of adenovirus type 12 with the deregulated human renin promoter.

Adenovirus early 1 (E1) region gene products, including E1A and E1B, are required for transcriptional regulation of viral and cellular promoters in infected and transfected culture cells and for transformation of primary rodent cells. Here, we established a line of transgenic mice carrying the E1 region gene of human adenovirus type 12 under the control of the human renin promoter, in which a neuroectodermal tumor derived from retroperitoneal, olfactory, and/or pelvic regions was heritably developed with varying degrees of incidence and the phenotype was successfully passed through six generations. The transgenes were located in the region E2-E3 bands of chromosome 7 with which no genetic linkage to neuroectodermal tumors was previously demonstrated, and expressed only in the tumors but not in another tissue examined. Notably, in addition to the expression of a neural marker gene N-CAM, the three nuclear oncogenes, c-, L-, and N-myc, were coexpressed in the tumors. These results suggest that E1A and E1B are cooperatively involved in the heritable formation of neuroectodermal tumors associated with co-expression of the three sets of myc family genes.

Adenovirus E1 Proteins↗

Primitive neuroectodermal tumor in the spinal epidural space--case report.

A 4-year-old boy presented with a rare case of an epidural tumor causing compression of the thoracic spinal cord manifesting as rapid worsening of gait disturbance. The tumor was grossly totally resected, and radiotherapy and chemotherapy were subsequently administered. The histological diagnosis was primitive neuroectodermal tumor. He has been free of recurrence for more than 6 years. Early tumor resection followed by chemotherapy and irradiation is recommended for patients with primitive neuroectodermal tumor and unstable symptoms.

Chemotherapy, Adjuvant↗

Betulinic acid triggers CD95 (APO-1/Fas)- and p53-independent apoptosis via activation of caspases in neuroectodermal tumors.

Betulinic acid (BA), a melanoma-specific cytotoxic agent, induced apoptosis in neuroectodermal tumors, such as neuroblastoma, medulloblastoma, and Ewing's sarcoma, representing the most common solid tumors of childhood. BA triggered an apoptosis pathway different from the one previously identified for standard chemotherapeutic drugs. BA-induced apoptosis was independent of CD95-ligand/receptor interaction and accumulation of wild-type p53 protein, but it critically depended on activation of caspases (interleukin 1beta-converting enzyme/Ced-3-like proteases). FLICE/MACH (caspase-8), considered to be an upstream protease in the caspase cascade, and the downstream caspase CPP32/YAMA/Apopain (caspase-3) were activated, resulting in cleavage of the prototype substrate of caspases PARP. The broad-spectrum peptide inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone, which blocked cleavage of FLICE and PARP, also completely abrogated BA-triggered apoptosis. Cleavage of caspases was preceded by disturbance of mitochondrial membrane potential and by generation of reactive oxygen species. Overexpression of Bcl-2 and Bcl-XL conferred resistance to BA at the level of mitochondrial dysfunction, protease activation, and nuclear fragmentation. This suggested that mitochondrial alterations were involved in BA-induced activation of caspases. Furthermore, Bax and Bcl-xs, two death-promoting proteins of the Bcl-2 family, were up-regulated following BA treatment. Most importantly, neuroblastoma cells resistant to CD95- and doxorubicin-mediated apoptosis were sensitive to treatment with BA, suggesting that BA may bypass some forms of drug resistance. Because BA exhibited significant antitumor activity on patients' derived neuroblastoma cells ex vivo, BA may be a promising new agent for the treatment of neuroectodermal tumors in vivo.

Antibiotics, Antineoplastic↗

Primitive neuroectodermal tumor of the cervix uteri. A case report.

Primitive neuroectodermal tumors (PNET) of the female genital tract are rare and more common in the ovary, but uncommon in the cervix uteri. A 26-year-old woman presented with suspect cervical smears. The conization specimen showed a small cell non-keratinised squamous cell carcinoma with involved margins. The patient underwent radical abdominal hysterectomy and pelvic lymphonodectomy. The microscopic examination showed a densely cellular tumor of small neuroendocrine cells with scanty cytoplasm and rosettes. Immunohistochemically, the cells were slightly positive for NSE and negative for S 100, GFAP, neurofilaments, squamous cell cytokeratin 1, vimentin, desmin and leukocyte common antigen. The diagnosis of PNET, stage pT1b1,N0, M0 was made. The patient underwent adjuvant pelvic radiation. Three years later, pulmonary metastases occured. Radiation therapy of the thorax and six courses of combination chemotherapy (5-FU and cis-platinium) could not prevent tumor progression. The patient died 4.2 years after diagnosis. The autopsy showed widespread lymphatic metastases and hepatic, pulmonal and skeletal metastases and a peritoneal carcinosis. The tumors are resistent to radio- and chemotherapy, and the prognosis is generally poor. Up to 15% foci of squamous or glandular differentiation occur in or adjacent to these tumors. So the authors favor the histogenesis from a pluripotent endocervical stem cell. The neuroendocrine component of mixed tumors improve the prognosis. Therefore, it is necessary to recognize this component.

Adult↗

A peripheral primitive neuroectodermal tumor with generalized bone metastases in a puppy.

A peripheral primitive neuroectodermal tumor (pPNET), most consistent with a human Ewing's sarcoma, is described in a 5-month-old male Australian Shepherd puppy. The first tumor site detected was in the left frontal bone of the skull with apparent subsequent rapid metastases to multiple sites in the axial and appendicular skeleton and bone marrow, kidneys, and perihyphophyseal meninges. Radiographically, all bone lesions were lytic and there was also a humeral bone fracture. Histologically, the tumor was diagnosed as a small round blue cell tumor. At this stage, the differential diagnosis included a lymphoma, rhabdomyosarcoma, and a PNET of the peripheral nervous system. However, the cells had positive expression of triple neurofilament antigens as detected immunocytochemically. The cells were negative for a broad panel of canine-specific leucocyte cell marker antigens for desmin, smooth muscle actin, synaptophysin, and CD99. Ultrastructurally, the cells contained occasional dense core neurosecretory granules and intermediate filaments with intercellular desmosomal-like junctions and abundant glycogen clusters. Based on the age of the dog, the clinical history, the distribution of gross lesions, histologic characteristics of a small round blue cell tumor, and immunocytochemical and ultrastructural evidence of neuroectodermal differentiation, a diagnosis of a pPNET similar to a human Ewing's sarcoma was made.

Animals↗

Melanotic neuroectodermal tumor of infancy: report of a case.

The melanotic neuroectodermal tumor of infancy (MNTI) is an uncommon benign neoplasm frequently detected in young infants, which has a predilection for the head and neck region, particularly maxilla. The purpose of this article is to present a documented case of MNTI and discuss clinical, radiological and histopathological features of the disease. The biological behavior of the tumor is emphasized.

Alveolar Process↗