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Expression of a new human THY-1 related antigen in Ewing's sarcoma and peripheral neuroectodermal tumors.

Ewing's sarcoma (ES), peripheral neuroectodermal tumor (PNET) and Askin's tumor of the chest wall share a reciprocal chromosomal translocation between the long arms of chromosomes 11 and 22 (q23-24; q12). In the absence of other distinguishing features this specific translocation is regarded as marker of a common and neuroectodermal origin for these rare tumors. A monoclonal antibody (HBA-71) developed in our laboratory has been found to recognize an unique ES and PNET associated antigen, which is also expressed in some normal tissues, including thymus, bone marrow, islets of Langerhans, ependyma and adenohypophysis. It is shown in this study that this HBA-71 antigen is closely related to the murine THY-1 antigens, major cell surface glycoproteins of thymocytes and brain in mice and rat. Both antigens have similar molecular ratios (18,000), amino acid compositions and sensitivity to tryptic digestion, show high cell surface expression, and binding of the appropriate antibodies to HBA-71 antigen triggers proliferation in thymocytes. The HBA-71 epitope may represent a primitive neuroectodermal marker of ES/PNET, or its expression may be directly linked to the reciprocal translocation invariably associated with HBA-71-positive ES and PNET tumors, which maps to the same region of chromosome 11 (q23-24) as the human Thy-1 gene.

Amino Acids↗

EWS-Fli1 antisense oligodeoxynucleotide inhibits proliferation of human Ewing's sarcoma and primitive neuroectodermal tumor cells.

The translocation t(11;22) is a common chromosomal abnormality detected both in Ewing's sarcoma and in primitive neuroectodermal tumor cells. The translocation results in an EWS-Fli1 fusion gene, made up of the 5' half of the EWS gene on chromosome 22 fused to the 3' half of the Fli1 gene on chromosome 11. Recent studies have evaluated possible roles of the fusion gene products. However, the biological significance of EWS-Fli1 is still unknown. Using a competitive polymerase chain reaction technique, we show here that there might be a correlation between the expression levels of the EWS-Fli1 fusion gene and the proliferative activities of Ewing's sarcoma and primitive neuroectodermal tumor cells. When the EWS-Fli1 expression is inhibited by antisense oligodeoxynucleotides against the fusion RNA, the growth of the tumor cells is significantly reduced both in vitro and in vivo. The data further indicate the growth inhibition of the cells by the antisense sequence might be mediated by G0/G1 block in the cell cycle progression. These results suggest that EWS-Fli1 may play an important role in the proliferation of the tumor cells, and the EWS-Fli1 fusion RNA could be used as a target to inhibit the growth of Ewing's sarcoma and primitive neuroectodermal tumor with the specific antisense oligonucleotide.

Cell Cycle↗

Development of multidrug resistance in a primitive neuroectodermal tumor cell line.

Drug resistance remains a formidable obstacle to the successful treatment of pediatric primitive neuroectodermal tumors. Resistance to chemotherapeutic agents may be related, in part, to expression of the multidrug resistance gene 1 (MDR1). The protein product of this gene, P-glycoprotein, confers resistance to multiple unrelated antineoplastic drugs. The cell line DAOY, derived from a primitive neuroectodermal tumor, was used as an in vitro model to examine the development of drug resistance. Cell lines resistant to actinomycin D were developed by the growth of DAOY in increasing concentrations of the drug. The IC50 (concentration of drug needed to induce a 50% reduction in cell growth) of the resultant lines to actinomycin D was more than 10 times that of the parental line. The resistant lines were cross-resistant to VP-16 (etoposide), despite lack of previous exposure to this drug. The resistance to actinomycin D was attenuated in the presence of verapamil, a known inhibitor of P-glycoprotein. The MDR1 gene was not expressed by the parental DAOY line at the messenger ribonucleic acid (RNA) and protein level. Expression of the MDR1 gene was documented in the resistant lines by RNA blot and immunoblot techniques. These results suggest that exposure to chemotherapeutic drugs can induce classical multidrug resistance in primitive neuroectodermal tumors.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

Molecular genetic analysis of a small bowel primitive neuroectodermal tumor.

We present a pediatric peripheral primitive neuroectodermal tumor (pPNET) localized exclusively to the small bowel. The tumor presented in an adolescent male and the diagnosis was confirmed by electron microscopy, CD99 immunopositivity, and molecular genetic analysis that demonstrated an EWS-FLI1 type 2 fusion transcript. This case report and a review of the literature underscore the considerable phenotypic overlap in EWS-related tumors in this site and the necessity for molecular genetic analysis to permit accurate classification.

Adolescent↗

Primitive peripheral neuroectodermal tumors Mayagüez Medical Center experience.

Primitive neuroectodermal or neuroepithelial tumors are names used to describe neoplasias composed of undifferentiated cells resembling germinal cells of the embryonic neural tube. These tumors are small round cell malignancies of the neural crest origin arising outside the central and sympathetic nervous system. They are described as peripheral and central neuroectodermal tumors related to the original malignant cell. A great number of tumors are described under this classification in spite of the fact that there is no an universal acceptance that these small-cell neoplasms, regardless of their primary site, are derived from immature neuroectoderm tissue. Because one tumor resembles others in terms of its phenotypic expression, multiple specific studies such as clinical profile, ultrastructural, immunocytochemical, and cytogenetic features should be studied, since no single clinical or laboratory marker is by itself diagnostic. However, there is a chromosomal reciprocal translocation, t(11;22)(q24;q12), which is unique to Primitive Neuroectodermal Tumor (PNET).

Adolescent↗

Expression of p67 (Munc-18) in adult human brain and neuroectodermal tumors of human central nervous system.

p67 (Munc-18), is a neuron-specific protein of 67 kDa, known for its ability to bind with syntaxin and also to copurify with neuronal cdc2-like kinase. Earlier, in situ hybridization and immunocytochemical analysis of rat trigeminal ganglion and hippocampal cells demonstrated the specific localization of p67 in nerve cells and its rich distribution in axons. In the present study, we have looked for p67 expression in normal human brain and various neuroectodermal tumors. Immunohistochemical and Western immunoblot analysis of normal human brain tissue using antibodies against the N- and C-termini of p67 demonstrated the specific localization of this protein in postmitotic neurons but not in glia. Among neuroectodermal tumors, expression of p67 was observed in 100% of the tumors of neuronal origin studied, especially in the mature neuronal cell population of these tumors. Western immunoblot analysis of non-neuronal neuroectodermal tumors failed to reveal the expression of this protein in majority of cases. However, in gliomas and meningiomas, mild cytoplasmic immunohistochemical staining of neoplastic cells was noted in 64.7% and 25% of cases, respectively. Observed mild immunohistochemical staining of these tumors could be due to immunoreactivity to low molecular weight degraded products of p67, as seen on Western blot. The findings suggest that p67, by virtue of its ability to be expressed in postmitotic neurons of adult human brain and in tumors of neuronal origin, may serve as a molecular tool to understand the growth and differentiation of the nervous system in general.

Adult↗

The multiple tumor suppressor 1/cyclin-dependent kinase inhibitor 2 gene in human central nervous system primitive neuroectodermal tumor.

The recently described multiple tumor suppressor 1/cyclin-dependent kinase inhibitor 2 (MTS1/CDKN2) gene, encoding the cyclin-dependent kinase 4 inhibitor p16, is mutated in a wide variety of tumor cell lines, including gliomas. To investigate the possible role of this gene in the genesis of the central nervous system primitive neuroectodermal tumor (PNET), four established PNET cell lines and 18 PNET surgical specimens were studied for deletions and mutations of the MTS1/CDKN2 gene. One of the four cell lines had homozygous deletion of the gene. No mutation in any of the three MTS1/CDKN2 exons was detected in the other three cell lines by single strand conformational polymorphism analysis. Eighteen surgical PNET specimens were studied for allelic and homozygous deletion at chromosome 9p21, the location of the MTS1/CDKN2 gene. No loss of heterozygosity was noted in 11 of the tumors, and no homozygous loss was noted in any tumor. Single strand conformational polymorphism analysis of the entire coding region of the MTS1/CDKN2 gene revealed no mutation within MTS1/CDKN2 in any tumor. Although deletion of MTS1/CDKN2 may occur in some PNET cell lines, neither deletion nor mutation of the gene is found in tumors before culture. The genesis of the human central nervous system PNET does not involve deletion or mutation of the MTS1/CDKN2 gene.

Base Sequence↗

Peripheral primitive neuroectodermal tumor: challenge for multimodal treatment.

The primitive neuroectodermal tumor (PNET) is an extremely aggressive soft tissue neoplasm that occurs in children and adolescents. We retrospectively reviewed our therapeutic experience with a multidisciplinary approach, combining surgery, chemotherapy, and radiation therapy. Treatment of PNET was carried out in compliance with the soft tissue protocol (CWS) from the German Society of Pediatric Oncology. Biopsy-proven diagnosis was followed by chemotherapy, which in all cases led to partial remission, allowing excision of the remainder of the tumor without mutilation. After excision, irradiation of the tumor site and two further sequences of chemotherapy were performed. When PNET of the paravertebral region caused symptoms of paralysis and immediate surgery was required, postoperative chemotherapy, a second-look operation, and irradiation were undertaken. Between 1986 and 1998 we treated 13 patients (median age 15 years). In five patients the PNET originated from the chest wall and in eight patients from the paravertebral and retroperitoneal region. Five patients died after 20 months on average, and the remaining eight patients are in full remission after 7, 16, 46, 55, 70, 74, 75, and 115 months, respectively. Close cooperation between surgeons and their pediatric and radiotherapy colleagues is obligatory when treating PNET. Chemotherapy as the first stage is mandatory to avoid a mutilating surgical procedure and intraoperative tumor cell dissemination.

Adolescent↗

Preliminary study of proton magnetic resonance spectroscopy in bone and soft tissue tumors: an unassigned signal at 2.0-2.1 ppm may be a possible indicator of malignant neuroectodermal tumor.

PURPOSE: To evaluate the utility of proton magnetic resonance spectroscopy in bone and soft tissue tumors, especially whether or not the N-acetyl aspartate signal (NAA) could be recognized in neurogenic tumors. MATERIALS AND METHODS: Forty-nine proton magnetic resonance spectroscopy studies were performed in 60 bone and soft tissue tumors. The patients were 28 males and 30 females. Eleven studies were incomplete, and were excluded from analysis. A point-resolved spectroscopy sequence (TR=1500 or 2000 ms, and TE=30, 60, 136, or 272 ms) was used on a 1.5-Tesla clinical MR scanner. RESULTS: An unassigned signal at about 2.0-2.1 ppm was recognized in six of 47 lesions: clear cell sarcoma (2/2), Ewing sarcoma (1/1), malignant fibrous histiocytoma (1/3), malignant schwannoma (1/1), and mucoepidermoid carcinoma (1/1). Neuroblastoma (1/1), primitive neuroectodermal tumor (1/1), and malignant melanoma (1/1) after chemotherapy or radiotherapy did not show this signal. This signal was not detected in neurofibroma (9/9), schwannoma (6/6), pheochromocytoma (2/2), or other mesenchymal tumors of non-neuroectodermal origin. CONCLUSIONS: The assigned signal at about 2.0-2.1 ppm was detected in a small percentage of bone and soft tissue tumors and could be suggestive of an untreated malignant tumor of neuroectodermal origin.

Adolescent↗

Peripheral primitive neuroectodermal tumor of the cerebellopontine angle.

Peripheral primitive neuroectodermal tumors are highly malignant small cell neoplasms. A 27-year-old female presented with a 6-month history of right-sided facial pain and progressive weakness of the facial muscles. She had non-pulsative tinnitus, progressive right hearing loss and facial palsy. T2-weighted MRI showed a heterogeneous hyperintense lesion invading the right internal auditory canal. Surgical removal was performed. Pathological examination showed sheets of small cells with irregular nuclei. Immunohistochemical studies demonstrated positive immunoreactivity for neuron-specific enolase, synaptophysin, chromogranin, vimentin, S-100 protein and p30-32 MIC-2 gene product. The patient was treated with chemotherapy (etoposide, vincristine, adriamycin, ifosfamide and actinomycin D) and radiotherapy. After 65 months of follow-up, the patient presented with cervical metastasis. Radical cervical dissection was performed and the patient was treated with a second course of chemotherapy. At control MRI after 29 months of follow-up the patient showed no signs of local recurrence or distant metastasis.

Adult↗

Peripheral primitive neuroectodermal tumor (PPNET) of pelvic origin: report of a case arising from an unusual location.

A peripheral primitive neuroectodermal tumor arising from the abdominopelvic cavity is reported in a 24-year-old young male without any previous remarkable pathology. He was admitted to our hospital with complaints of urinary symptoms (acute urinary retention) and mild intestinal occlusion that had been present for three months. Physical examination and CT scan revealed a pelvic mass occupying the entire pelvic cavity. The diagnostic workup included a CT-guided biopsy which defined the tumor as a sarcomatous type. Radical surgery was performed including tumor resection, pelvic exenteration (bladder and prostate gland) and urinary and fecal diversion. Adjuvant chemotherapy (VAIA) was delivered once the histology was confirmed. We reviewed the available literature focusing on the varied nomenclature of this tumor (peripheral neuroepithelioma, Askin's tumor, Ewing's extraosseous tumor, peripheral adult neuroblastoma, peripheral primitive extracranial neuroectodermal tumor (PPNET), the clinical features, the role of diagnostic imaging techniques, pathologic assessment and controversial therapeutic management. In addition, the prognosis and survival of this rare condition were analyzed.

Adult↗

Melanotic neuroectodermal tumor of infancy: case report.

INTRODUCTION: Melanotic neuroectodermal tumor of infancy (MNTI) is a rare tumor, locally aggressive, usually originated from maxilla and mandible and rarely from the skull. A case of a 4 month-old child presenting a bulging lesion in the midline of the occipitoparietal region with progressive growth is reported. CASE REPORT: The neurologic examination had normal developmental milestones. Computerized tomography scan and magnetic resonance Image showed a highly enhancing tumor, dislocating anteriorly and inferiorly the superior sinuses. In order to prevent excessive bleeding, surgical resection was performed in three stages, with complete removal. CONCLUSION: Based on the absence of tumor recurrence, we believe in a favorable neurological prognosis and in a possible of cure, although the patient was not submitted to any adjuvant treatment.

Humans↗

Betulinic acid: a new chemotherapeutic agent in the treatment of neuroectodermal tumors.

We identified betulinic acid (BetA) as a new cytotoxic agent active against neuroectodermal tumor cells including neuroblastoma, medulloblastoma, glioblastoma and Ewing's sarcoma cells representing the most common solid tumors of childhood. BetA induced apoptosis independent of wild-type p53 protein and accumulation of death-inducing ligand/receptor systems such as CD95. BetA had a direct effect on mitochondria resulting in the release of soluble apoptogenic factors such as cytochrome c or AIF from mitochondria into the cytosol where they induced activation of caspases. Overexpression of the anti-apoptotic proteins Bcl-2 or Bcl-XL that blocked loss of the mitochondrial membrane potential and cytochrome c release from mitochondria conferred resistance to BetA at the level of mitochondrial dysfunction, protease activation and nuclear fragmentation. Neuroblastoma cells resistant to CD95- or doxorubicin-triggered apoptosis remained sensitive to treatment with BetA suggesting that BetA may bypass some forms of resistance. Moreover, BetA exhibited potent antitumor activity on primary tumor cell cultures from all neuroblastoma (4/4), all medulloblastoma (4/4) and most glioblastoma patients (20/24) ex vivo. These findings suggest that BetA may be a promising new agent in the treatment of neuroectodermal tumors in vivo.

Antineoplastic Agents, Phytogenic↗

Primitive neuroectodermal tumor (PNET) of the uterine isthmus.

Primitive neuroectodermal tumors (PNETs) of the uterus are very rare. The histogenesis of these tumors is still unknown and the differential diagnosis includes a wide variety of tumor entities. We describe a rare case of a 68-year-old female who presented with persistent vaginal bleeding. Physical examination and CT-scan revealed a large tumor in the uterus. Macroscopically the tumor involved the uterine isthmus. Histological and immunohistochemical examination showed that the tumor fulfilled the diagnostic criteria set for PNET. Only a very small number of cases of PNETs of the uterus have been reported in the literature, thus no definitive conclusions concerning the therapeutic management and prognosis have been ascertained.

Aged↗

Thoracoabdominal peripheral primitive neuroectodermal tumors in childhood: radiological features.

Peripheral primitive neuroectodermal tumors (PNET) are extremely uncommon, malignant neoplasms affecting mostly children and young adults. We retrospectively reviewed the clinical data and radiological studies of four such cases. All cases were pathologically proven. Plain films, US, and CT scans were used. The youngest child had a huge pelvic tumor and two adolescents each had a chest wall (Askin) tumor. The fourth patient had a most unusual location of the PNET in the anterior mediastinum. The CT findings are emphasized. We emphasize that the markedly abnormal CT findings are not specific for PNET.

Abdominal Neoplasms↗

[Molecular genetic detection of t(11;22)(q24;12) translocation in Ewing sarcoma and malignant peripheral neuroectodermal tumors].

Ewing's sarcomas and malignant peripheral neuroectodermal tumors (MPNTs) show very little evidence of differentiation and lack characteristic morphological features at the light-microscopic level. These malignancies have always presented a significant differential diagnostic challenge to the pathologist. Electron microscopy, immunohistochemical staining for neural antigens such as neuron-specific enolase (NSE), Leu 7, synaptophysin and, more recently, the detection of Mic-2 gene expression have been included in the routine histopathological diagnostic procedure. However, the expression of these antigens is not restricted to this entity. Thus, further modalities are required to prove diagnostic reliability. One consistent feature of the Ewing's sarcoma family is the presence of the reciprocal chromosomal t(11;22)(q24;q12) translocation. Recent cloning of the t(11;22) break point has led to the identification of the genes involved in this translocation. This provides the possibility of molecular genetic detection of the t(11;22) translocation in Ewing's sarcomas and MPNTs. We have established a method using reverse transcription and the polymerase chain reaction (RT-PCR) for the detection of the specific gene fusion transcript caused by the 11;22 translocation. The validity of our approach was proved by analyzing Ewing's tumor cell lines and tissue material obtained from primary biopsies and tumor resections. Molecular genetic detection of the 11;22 translocation by RT-PCR analysis should perhaps be included in the diagnostic work-up of suspected Ewing's sarcoma and MPNT.

Bone Neoplasms↗

Primary primitive neuroectodermal tumor of the urinary tract.

Primary primitive neuroectodermal tumor (PNET) of the urinary tract is a rare disease with aggressive behavior and poor prognosis. We analyzed 851 cases of urinary tract malignancies in our hospital between 1984 and 2004. Only three (0.035%) cases with PNET of the urinary tract were identified. Presenting symptoms included flank pain and hematuria. The first case was a 44-year-old man with left renal PNET who underwent hand-assisted laparoscopic radical nephrectomy and adjuvant chemotherapy. There was no recurrent tumor at the 4-year follow-up. The second case was a 75-year-old woman with right renal PNET with inferior vena cava (IVC) thrombosis extending to the right atrium. The patient underwent right radical nephroureterectomy and IVC thrombectomy with cardiopulmonary bypass. She died of metastatic disease 7 months later. The third case was a 45-year-old man with left ureteral PNET. Left ureteral segmental resection and partial cystectomy were performed. Tumor recurrence was noted 7 years later. The patient died of disseminated disease 1 year after the discovery of recurrence. Urinary tract PNET appears to be an aggressive malignancy. Long-term survival is possible if complete resection is performed at an early stage.

Adult↗

[An operative case of primitive neuroectodermal tumor in the posterior mediastinum].

A primitive neuroectodermal tumor (PNET) is very rare and the prognosis of this tumor is poor. A 32-year-old woman complaining of dysphagia and back pain was admitted to our hospital for the posterior mediastinal tumor. The tumor originated from the muscle layer of esophagus and en bloc resection of the tumor combined with the affected part of esophagus was performed. Histopathological diagnosis of the resected tumor was PNET. She received adjuvant chemotherapy. Eight months after the surgery, recurrent tumors in the right mediastinum and the retrooperitoneal space was resected completely. But after the second surgery, dissemination occurred recurrently. These recurrent tumors revealed high sensitivity for radio-therapy. However, she died of rapid recurrence 22 months after the first surgery. In Japan, our case is the second case of PNET in the posterior mediastinum and the first case of PNET arising from the muscle layer of esophagus.

Adult↗