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Results for “Neuroectodermal Tumors, Primitive”

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PubMed1997

Stem cell factor suppresses apoptosis in neuroblastoma cell lines.

Stem cell factor (SCF) is a glycoprotein growth factor produced by marrow stromal cells that acts after binding to its specific surface receptor, which is the protein encoded by the protooncogene c-kit. SCF synergizes with specific lineage factors in promoting the proliferation of primitive hematopoietic progenitors, and has been administered to expand the pool of these progenitors in cancer patients treated with high-dose chemotherapy. SCF and its c-kit receptor are expressed by some tumor cells, including myeloid leukemia, breast carcinoma, small cell lung carcinoma, melanoma, gynecological tumors, and testicular germ cell tumors. Previous studies of SCF in neuroblastoma have produced conflicting conclusions. To explore the role of SCF in neuroblastoma, we studied five neuroblastoma lines (IMR-5, SK-N-SH, SK-N-BE, AF8, and SJ-N-KP) and the neuroepithelioma line CHP-100. All lines expressed mRNA for c-kit and c-kit protein at low intensity as measured by flow cytometry, and secreted SCF in medium culture as shown by ELISA. Exogenous SCF did not modify 3H thymidine uptake in the neuroblastoma and neuroepithelioma cell lines. After 6 days' culture in the presence of anti-c-kit, the number of viable neuroblastoma cells was significantly lower than the control, and terminal deoxynucleotidyl transferase assay showed a substantial increase of apoptotic cells: The percentage of positive cells was 1-3% in the control lines, whereas in the presence of anti c-kit it varied from 29% of SK-N-BE to 92% of CHP-100. After 9 days' culture in the presence of anti-c-kit, no viable cells were detectable. These data indicate that SCF is produced by some neuroblastoma cell lines via an autocrine loop to protect them from apoptosis.

Antibodies, Monoclonal↗

PubMed2005

Lumbar region intra-spinal primitive neuroectodermal tumour (PNET) combined with neurofibromatosis type 1.

Primitive neuroectodermal tumours (PNET) are aggressive neoplasias that are diagnosed, usually, in infancy. Their appearance in adulthood is rare and, exceptionally, in association with neurofibromatosis type I (NF-1). We present a case of a 37 year-old man with NF-1 combined with PNET in the intra-arachidial lumbar region. Diagnosis was by Nuclear Magnetic Resonance (NMR) and biopsy of soft tissue mass which showed a PNET with undifferentiated round cells and immunohistochemically positive for CD99, neurone-specific enolase, synaptophys in and LEU-7. Surgery was performed with spine decompression and resection of 80% of the tumour, with symptoms improvement. Radiotherapy was administered on the lumbosacral column, but only up to 30 Gy because of severe actinic enteritis and pan-cytopenia grade III. Six months later, the patient was hospitalized with deterioration in his overall clinical status with multi-organ involvement. The patient died and an autopsy was performed. The initial treatment of the PNET is surgery and, if possible, the radical extirpation of the tumour. Administration of radiotherapy and chemotherapy appears to increase survival. We comment on the clinical, histological, cytological and immunohistochemical aspects together with a review of the literature. To the best of our knowledge this is the first documentation of such a case.

Adult↗

PubMed2001

Primary malignant neuroepithelial tumors of the kidney: a clinicopathologic analysis of 146 adult and pediatric cases from the National Wilms' Tumor Study Group Pathology Center.

Primary malignant neuroepithelial tumors of the kidney (NETKs) comprise a group of primitive, highly malignant neoplasms that histologically and clinically are not well characterized. A large cohort of 146 of these tumors, occurring in adults and children, has been collected at a single depository site, the National Wilms' Tumor Study Group (NWTSG) Pathology Center. The authors undertook a systematic retrospective review of the histologic, ultrastructural, and clinical features of these tumors, based on materials collected by the NWTSG and the consultation files of one of the authors (J.B.B.). Histologic features were generally those of primitive neural tumors with varying amounts of rosettes and neuropil; however, a large proportion of cases displayed unusual features such as spindle cells, ganglion cells, clear cell sarcoma-like foci, rhabdoid cells, epithelioid cells, and organoid foci. CD99 staining had been performed on 69 cases and showed membranous staining in 65. The NETKs were present in patients with a wide age spectrum, ranging from 1 month to 72 years (median, 18 years). EWS/FLI1 fusion analysis using reverse transcriptase-polymerase chain reaction and immunohistochemical stains for cytokeratin, chromogranin, and epithelial membrane antigen were performed successfully on a subset of 45 cases with available paraffin blocks. Only 13 of the 45 were fusion-positive, and there was no correlation between fusion status and histology, presence of rosettes, ultrastructural features, or cytokeratin positivity. CD99-negative cases were usually fusion-negative (six of seven cases), and all three chromogranin-positive cases were fusion-negative. Tumor staging, performed on 72 clearly defined and quantifiable cases by using NWTSG criteria, indicated that these are aggressive tumors, because only six were Stage 1, compared with 16 Stage 2, 31 Stage 3, and 19 Stage 4 lesions. The authors conclude that NETKs are a somewhat diverse group of generally aggressive, high-grade lesions that may present in a wide age range and are difficult to characterize without immunohistochemistry and cytogenetics/molecular biology.

Adolescent↗

PubMed1998

Primitive neuroectodermal tumours: anatomic location, extent of surgery, and outcome.

BACKGROUND/PURPOSE: Primitive neuroectodermal tumours (PNET) are rare tumours sharing similar histology, immunohistochemistry, and cytogenetics to Ewing's sarcomas. The aim of the study was to document the effect of site of origin and the completeness of surgical excision on the outcome in infants and children with PNET. METHODS: All patients (n = 26) with PNET treated in our hospital during the last 6 years were included in the study. The diagnosis was based on the histopathologic findings and a positive MIC2 antibody test. The tumours were classified according to the Intergroup Rhabdomyosarcoma Study III, and were treated according to the UKEESG protocol for Ewing's Sarcoma. RESULTS: Complete remission (CR) was achieved in 52% of the patients completing their chemotherapy. Overall, survival was 42% (11 of 26). Tumours from the paraspinal and scapula areas responded relatively well (CR, 83%), whereas abdominal PNET did not respond to treatment. Tumours arising from the head, neck, or chest had an intermediate prognosis (37% survival). Three of the 10 patients who had a complete excision of the tumour died of progressive disease. CONCLUSIONS: Complete surgical excision reduced the risk of local recurrence but did not prevent metastatic spread. These data indicate that PNET have a worse prognosis and different favourable sites than other sarcomas. New treatment strategies are necessary for these rare tumours.

Abdominal Neoplasms↗

PubMed1998

Utility of cytokeratin subsets for distinguishing poorly differentiated synovial sarcoma from peripheral primitive neuroectodermal tumour.

AIMS: Poorly differentiated synovial sarcoma (PDSS) is a round cell sarcoma that may be difficult to distinguish from other round cell sarcomas, such as peripheral primitive neuroectodermal tumour (pPNET), on histological examination alone. Furthermore, these two tumours may show overlapping immunophenotypes, as some cases of PDSS express CD99, and, on the other hand, pPNET may express epithelial markers. The goal of this study was to determine the utility of cytokeratin (CK) subsets in distinguishing between these two lesions. METHODS AND RESULTS: We evaluated 13 cases of pPNET with RT-PCR detected EWS/FLI-1 fusion transcript and 21 cases of PDSS for the immunohistochemical expression of CK7 and CK19. All cases of PDSS had areas of recognizable monophasic or biphasic synovial sarcoma that expressed at least one epithelial marker. Thirteen of 21 (62%) PDSS stained with AE1/AE3. CK7 and 19 were expressed in 11 (52%) and nine (43%) cases, respectively. Although six of 19 (32%) PDSS demonstrated cytoplasmic staining for CD99, none showed a membranous pattern of immunoreactivity. In contrast, 12 of 13 (92%) pPNET showed strong membranous immunoreactivity for CD99. Four tumours (31%) showed focal staining with AE1/AE3, two of which (15%) stained for CK19. CK7 was not detected in any of the pPNETs. CONCLUSIONS: Although AE1/AE3 may be found in up to 31% of cases of pPNET, the expression of CK7 makes this diagnosis less likely.

12E7 Antigen↗

PubMed2002

Loss of caspase-8 mRNA expression is common in childhood primitive neuroectodermal brain tumour/medulloblastoma.

Upon binding of tumour necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL), the agonistic TRAIL receptors DR4 and DR5 activate caspase-8 leading to apoptosis. In primitive neuroectodermal brain tumour (PNET) cell lines, TRAIL-induced apoptosis was recently shown to correlate with caspase-8 mRNA expression (Grotzer MA, Eggert A, Zuzak TJ, et al. Oncogene 2000, 19, 4604-4610). In this study, we analysed the expression of the TRAIL death pathway in 27 primary PNET/medulloblastoma. As shown by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), all PNET/medulloblastoma evaluated expressed DR5, the adapter protein FADD and caspase-3, but only 48% expressed caspase-8. The mRNA expression of caspase-8 was significantly lower in primary PNET/medulloblastoma compared with normal brain samples. PCR revealed >75% methylation of the caspase-8 promoter region in three of seven PNET cell lines and in 55% of the primary PNET/medulloblastoma evaluated. In the PNET cell lines, the methylation status correlated with the caspase-8 mRNA expression. We conclude that loss of caspase-8 gene expression is common in PNET/medulloblastoma suggesting that suppression of death receptor induced apoptosis may play an important role in the pathogenesis of this common childhood brain tumour.

Adaptor Proteins, Signal Transducing↗

PubMed1998

Human primitive neuroectodermal tumour cells behave as multipotent neural precursors in response to FGF2.

Primitive neuroectodermal tumours (PNET) are thought to derive from the malignant transformation of pluripotent CNS precursors although this hypothesis has yet to be tested in vitro. Here we show that cells of a human PNET cell line 'Dev' express functional fibroblast growth factor (FGF) receptors (FGFR) and respond to FGF2 as multipotent CNS precursors. FGF2 induces tyrosine phosphorylation of FGFR-1 and FGFR-2 and many cellular substrates including MAP kinases and stimulates proliferation. Cells detach from plastic substrates and proliferate to form large clusters of undifferentiated cells. After adhesion to polylysine, cells migrate out from the clusters and differentiate. The majority of differentiated cells express neuronal phenotypes but distinct subpopulations express oligodendrocytic and astrocytic markers. Mature neural differentiation markers are not otherwise detected in Dev cells in defined medium. Identical results were obtained with 12 monoclonal subclones as well as the parent cell line, confirming that Dev cells are multipotent. This extends evidence that multipotent CNS precursors are the cellular substrate from which certain PNET develop and shows that FGF2 is a potent proliferation and differentiation inducer for PNET cells in vitro, suggesting that FGF2 may also modulate the evolution of PNET in vivo. Finally our results suggest that PNET cell lines may provide models to elucidate the biology of human multipotent CNS precursors.

Biomarkers↗

PubMed2001

Neuroendocrine tumors in the brain.

Somatostatin and other neuropeptides are expressed in tumors originating from neuronal precursors and paraganglia, namely medulloblastoma, central Primitive Neuro-Ectodermal Tumors (cPNETs), neurocytoma, gangliocytoma. olfactory neuroblastoma, paraganglioma. In medulloblastoma, the most common malignant tumor in childhood, there is an extensive expression of somatostatin in addition to somatostatin receptors (SSTR) type 2. Although density of SSTR-2 and intensity of expression of somatostatin genes have no prognostic significance in medulloblastoma. their presence may bring along important information on oncogenesis and relate medulloblastoma to cPNETs. Radio-labeled octreotide scintigraphy may be useful in the follow-up of these patients. allowing differentiation between scar and tumoral tissue. Moreover, on the basis of octreotide-induced inhibition of cell proliferation in medulloblastoma, a trial with octreotide in patients with recurrent or high-risk tumor is warranted. Meningiomas and low-grade astrocytic gliomas, even if not displaying a clear neuroendocrine phenotype, have high levels of SSTR-2. In meningiomas, SSTRs-scintigraphy is not part of the routine pre-operative assessment; moreover, a therapeutic trial with somatostatin-analogues in patients with recurrent or inoperable meningiomas should be carried-out with great caution, because somatostatin and octreotide slightly increase cell proliferation in cultured meningiomatous cells. Low-grade gliomas (WHO grade 2), and a smaller fraction of anaplastic astrocytomas, express SSTR-2, while glioblastomas usually do not. Unfortunately, radiolabeled-octreotide scintigraphy is not useful in the differential diagnosis of gliomas, because the results are altered by the disruption of the blood brain barrier (BBB); in addition, radionuclide-labeled somatostatin analogues are not useful in the therapy of low-grade gliomas, because the intact BBB prevents them from reaching the target SSTR-2. Recently, a pilot study in gliomas, has proposed the use of a radio-labeled somatostostatin analogue with a loco-regional approach in order to overcome the intact BBB.

Antineoplastic Agents↗

PubMed1997

The use of paediatric chemotherapy protocols at full dose is both a rational and feasible treatment strategy in adults with Ewing's family tumours.

BACKGROUND: Ewing's sarcoma and primitive neuroectodermal tumour (ES/PNET) are rare, limiting opportunities for therapy studies in adults. Chemotherapy regimens adapted from paediatric studies are often used for adults but concerns about poor outcome and treatment toxicity may adversely affect drug dose intensity. We present our experience using a paediatric protocol at full dose. PATIENTS AND METHODS: Records of 34 patients with ES/PNET who received the IVAD chemotherapy regimens were reviewed. Received drug dose intensity, toxicity and survival data were collected. RESULTS: Received dose intensity in 30 evaluable patients was 0.92 compared to the standard IVAD schedule. Myelosuppression was the major toxicity, 83% of patients experienced grade 4 neutropenia. There was no major renal or cardiac toxicity. In patients without metastases at presentation, five-year overall survival was 63% and progression free survival was 39%. Tumour burden at presentation was statistically significantly associated with survival (P = 0.002). The five-year survival rate of 80% in patients presenting with low volume non metastatic disease was equivalent to published paediatric series. CONCLUSIONS: Although the IVAD chemotherapy regimens are myelotoxic in adults, they can be given safely. We recommend that adults with ES/PNET should be included in current multicentre, multidisciplinary treatment studies directed at children.

Adolescent↗

PubMed2005

Genetic heterogeneity in supratentorial and infratentorial primitive neuroectodermal tumours of the central nervous system.

AIMS: Medulloblastoma (MB), a kind of infratentorial primitive neuroectodermal tumour (PNET), is the most frequent malignant brain tumour in childhood. In contrast, supratentorial PNET (sPNET) are very infrequent tumours, but they are histologically similar to MB, although they present a worse clinical outcome. We investigated the differences in genetic abnormalities between sPNET and MB. METHODS AND RESULTS: We analysed 20 central PNET (14 MB and six sPNET) by conventional comparative genomic hybridization (CGH) in order to determine whether a different genetic profile for each tumour exists. Isochromosome 17q was detected in four of the 14 MB cases, but not in any sPNET. Gains at 17q and 7 happened more frequently in MB, and those at 1q in sPNET. Losses at chromosome 10 were detected only in MB, while losses at 16p and 19p happened more frequently in sPNET. A new amplification site, on 4q12, was detected in two MB. CONCLUSIONS: Central PNET are a heterogeneous group of tumours from the genetic point of view. The present and previous data, together with further results from larger series, might contribute to the establishment of specific treatments for supratentorial and infratentorial PNET.

Brain Neoplasms↗

PubMed2002

Imaging of peripheral PNET: common and uncommon locations.

AIM: We present the imaging features of peripheral primitive neuroectodermal tumour (PNET) in eight children, highlighting the unusual locations of this tumour in three children. MATERIALS AND METHODS: At presentation, the tumours were studied with magnetic resonance imaging (MRI; n = 6), computed tomography (CT; n = 7) and ultrasound (US; n = 1). The diagnoses were confirmed histologically (n = 8), immunohistochemically (n = 8), by cytogenetics (n = 3) and electron microscopy (n = 1). Correlation with gross pathology, histology, treatment and outcome were obtained. RESULTS: The tumours were located in the chest wall (n = 2), shoulder, pelvis, small bowel mesentery, adrenal gland, dura mater and skin and subcutaneous tissue of the abdominal wall (n = 1 each). Peripheral PNET arising from the small bowel mesentery, adrenal gland and dura mater have not been previously reported in the English literature. The tumours were mainly large (mean size: 10.6 cm) and infiltrative. All tumours were heterogeneously hyperintense on T2-weighted MRI, heterogeneously iso/hypodense on CT and had variable contrast enhancement. Most tumours were heterogeneously hypointense to muscle on T1-weighted MRI. US showed a hypoechoic mass with a cystic component. CONCLUSION: Peripheral PNET can occur in unusual locations. The clinical and imaging features of peripheral PNET are non-specific, making tissue diagnosis essential. PNET should be included in the differential diagnosis of aggressive soft tissue tumours in children.

Adolescent↗

PubMed1995

Differential expression of beta 1, beta 3 and beta 4 integrins in sarcomas of the small, round, blue cell category.

Integrins are a large and complex family of membrane spanning alpha beta heterodimeric cell surface glycoproteins mediating cell/cell and cell/matrix interactions. Small, round, blue cell sarcomas (SRBCS) are a group of poorly differentiated tumours of various and in part uncertain histogenesis displaying similar cytomorphology. Among them are rhabdomyosarcomas (RMS), ganglioneuroblastomas [(G)NB], primitive peripheral neuroectodermal tumours (pPNET) and Ewing's sarcomas (ES). Thirty-two SRBCS were studied immunohistochemically for the distribution of beta 1, beta 3 and beta 4 integrins in situ. We found complex and to some extent differential patterns of beta 1, beta 3 and beta 4 integrin subunit expression in different types of SRBCS: all of the sarcomas studied were consistently beta 1+, beta 4-, alpha 2-. Four of nine RMS were completely negative for all other integrin subunits studied while one RMS was alpha 5+ throughout and three RMS were focally alpha 5+. Three RMS expressed the alpha 6 and alpha v chains. In contrast to RMS, pPNET and ES, all of which were alpha 1-, alpha 3-, (G)NB were alpha 3+ and frequently co-expressed alpha 1. The eight pPNET and seven ES studied showed a similarly restricted integrin profile that was limited to the expression of beta 1 and alpha 5 in nearly all cases. In summary, RMS were beta 1+, alpha 1-, alpha 3- and heterogeneously expressed alpha 5 and alpha 6. (G)NB were generally beta 1+, alpha 1+, alpha 3+, alpha 5-, alpha 6-. pPNET and ES were beta 1+, alpha 1-, alpha 3-, alpha 5+, alpha 6-. The data illustrate a complex expression pattern of various integrins in SRBCS, a differential expression pattern of some of the integrin subunits among different types of SRBCS and almost identical integrin profiles in pPNET and ES.

Ganglioneuroblastoma↗

PubMed2003

Peripheral primitive neuroectodermal tumour of the left maxillary sinus.

Peripheral primitive neuroectodermal tumours (pPNETs) are highly malignant, small-cell neoplasms found mainly in children and young adults. Recent advances in immunohistochemistry and genetic typing have led to reports of a close relationship between pPNET and the previously difficult-to-classify Ewing's sarcoma. We report a case of pPNET involving the left maxillary sinus in a 23-year-old female who presented with a 2-month history of unilateral left-sided nasal obstruction, rhinorrhoea and recurrent bloody nasal discharge. A CT scan of the paranasal sinuses showed a large mass (10 x 7 x 3 cm3) arising from the left maxillary sinus, with signs of bone destruction and invasion of the left orbital floor and pterygomaxillary fossa. MRI revealed a heterogeneous hyperintense signal on a T2-weighted image in the left maxillary sinus. The tumour was surgically removed by means of external lateral rhinotomy. Pathological examination showed a sheet of small cells with irregular nuclei. Immunohistochemical studies demonstrated positive immunoreactivity for neurone-specific enolase, synaptophysin, chromogranin, vimentin, S-100 protein and p30-32 MIC-2 gene product. The patient was treated with chemotherapy consisting of cyclophosphamide, vincristine, adriamycin and actinomycin D, together with radiotherapy to a total tumour dose of 60 Gy. After 59 months of follow-up, the patient remained free of disease and a repeat MRI scan was normalized, with no sign of residual tumour.

Adult↗

PubMed2000

Induction of cell death by basic fibroblast growth factor in Ewing's sarcoma.

Ewing's sarcoma is thought to arise after developmental arrest of primitive neural cells during embryogenesis. Because basic fibroblast growth factor (bFGF) has a critical role in the regulation of cell survival, proliferation, and differentiation during embryogenesis, we have tested the hypothesis that bFGF and FGF receptors may contribute to the development of Ewing's sarcoma and may provide a mechanism for the modulation of their behavior. All four of the Ewing's sarcoma cell lines examined expressed bFGF and FGF receptors, which were detected by immunofluorescence and Western blotting. bFGF-induced a significant dose-dependent decrease in Ewing's sarcoma cell proliferation on plastic and reduced anchorage-independent growth in soft agar. Unexpectedly, this decrease in cell number reflected bFGF-induced apoptosis and necrosis, as demonstrated by electron microscopy, binding of annexin V, and staining with acridine orange. Induction of cell death was dependent on dosage of, and period of exposure to, bFGF. bFGF did not induce differentiation of Ewing's sarcoma cells in either the presence or the absence of serum or nerve growth factor. Treatment of NuNu mice with bFGF decreased growth of the highly tumorigenic Ewing's sarcoma cell lines. Histologically tumors grown in the NuNu mice treated with bFGF were less cellular than those in control mice, and showed an increased level of apoptotic nuclei. This is in contrast to the mitogenic effect bFGF has in most other cancer cells. In summary, bFGF decreases Ewing's sarcoma growth in vitro and in vivo by the induction of cell death. This novel observation may provide a new therapeutic strategy for Ewing's sarcomas.

Animals↗

PubMed2007

Paediatric PNET: pre-surgical MRI features.

AIM: To describe the preoperative magnetic resonance imaging (MRI) characteristics of primitive neuroectodermal tumours (PNETs), in particular the diffusion-weighted imaging (DWI), MR spectroscopy (MRS) features and cerebrospinal fluid (CSF) tumour dissemination. MATERIAL AND METHODS: Twelve patients with PNETs were reviewed: nine with medulloblastoma and three with supratentorial PNETs (SPNETs). The MRI examination included contrast-enhanced intracranial and spinal MRI, and in some patients, gradient recalled echo, fluid-attenuated inversion recovery (FLAIR), DWI, and MRS. RESULTS: All PNETs were either hypointense or isointense on T1-weighted images. Ten of the 12 tumours were either isointense or hypointense on T2-weighted images, and 11 were isointense on FLAIR images. Patients with SPNETs had large, vascular and haemorrhagic tumours. On DWI, all PNETs were hyperintense and had restricted apparent diffusion coefficient. MRS (two patients with medulloblastoma and one with a SPNET), showed elevated choline, decreased N-acetyl aspartate, and a small taurine peak in all three patients. Intraspinal tumour dissemination, visible as uniform or nodular enhancement coating the conus medullaris, was detected in six of 12 patients, two of whom also had intracranial dissemination. CONCLUSION: PNETs have a characteristic imaging appearance on FLAIR, DWI and MRS, which may help in differentiating these highly cellular neoplasms from other tumours. There is CSF tumour dissemination in a high proportion of patients, and spinal imaging is important for disease staging and to formulate treatment protocols.

Aspartic Acid↗

PubMed1997

Somatic mutations in the human homologue of Drosophila patched in primitive neuroectodermal tumours.

The naevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by multiple developmental defects and cancer susceptibility, in particular to basal cell carcinomas (BCCs). Medulloblastomas, primitive neuroectodermal tumours (PNETs) arising in childhood, occur in about 3-5% of NBCCS patients and a subset of PNETs was previously found with allelic imbalance at 9q22-q23, the region containing the gene for NBCCS (PTCH). We have analysed tumour DNA samples from 37 unrelated patients with sporadic PNETs and five medulloblastoma cell lines for PTCH mutations using an exon-by-exon single strand conformation polymorphism assay. We found three missense mutations, which affect conserved residues in transmembrane domains of the gene product and in the extracellular loop implicated in binding sonic hedgehog, one 2 bp deletion and an exon skipping splice site mutation. Most mutations were associated with the absence of the wild-type allele and were found in tumours exhibiting loss of heterozygosity (LOH) at loci flanking PTCH. The finding of LOH at 9q22-q23 in most mutated tumours while present in only three out of 26 tumours, in which a mutation was not identified, implicates PTCH as the target gene in PNETs with LOH at 9q22-q23 and deficient PTCH in the development of a subset of these tumours. Since all observed mutations were absent in the germ-line, a sporadic medulloblastoma developing as the first symptom of NBCCS is likely to be a very uncommon event.

Adolescent↗

PubMed2002

Molecular genetic analysis of the TP53, PTEN, CDKN2A, EGFR, CDK4 and MDM2 tumour-associated genes in supratentorial primitive neuroectodermal tumours and glioblastomas of childhood.

Supratentorial primitive neuroectodermal tumours (sPNETs) are malignant central nervous system tumours of childhood which are histologically characterized by poorly differentiated neuroepithelial cells with the capacity for divergent differentiation into glial, neuronal, myogenic or melanotic lines. The histological differential diagnosis between sPNET and glioblastoma multiforme (GBM) may be difficult, particularly as GBMs can sometimes demonstrate a poorly differentiated PNET-like phenotype. To identify molecular genetic markers that may distinguish sPNET and GBM, we investigated 12 cerebral sPNETs and six GBMs from paediatric patients for genetic alterations of the TP53, PTEN, CDKN2A, EGFR, CDK4 and MDM2 genes, as well as for allelic loss on chromosome arms 10q and 17p. Mutations of the TP53 tumour suppressor gene were found in one of 12 sPNETs (8%) and two of six GBMs (33%). None of the sPNETs but two of six GBMs (33%, including one GBM with a TP53 mutation) showed allelic losses on chromosome arm 17p. PTEN mutations were detected in one of 12 sPNET (8%) and one of six GBMs (17%). None of the sPNETs and GBMs carried a homozygous deletion involving the CDKN2A tumour suppressor gene. No amplification of the EGFR, CDK4 or MDM2 proto-oncogenes was detected. Taken together, our results indicate that paediatric GBMs differ from sPNETs by a higher incidence of allelic losses on 17p and TP53 mutations. In addition, the patterns of genetic alterations in sPNETs and paediatric GBMs appear to be distinct from those in cerebellar medulloblastomas and adult GBMs, respectively.

Adolescent↗

PubMed1998

Engagement of CD99 induces apoptosis through a calcineurin-independent pathway in Ewing's sarcoma cells.

Programmed cell death (PCD) is a prominent feature of the development of the immune and nervous systems. In both systems, widespread PCD occurs in primitive progenitor cells during development. In this study, we demonstrated that Ewing's sarcoma (ES) cells, undifferentiated neural precursors, underwent apoptosis upon engagement of CD99 with anti-CD99 monoclonal antibody. Apoptosis via CD99 occurred only in the undifferentiated state of ES cells, but not in differentiated ES cells. CD99-induced apoptosis in ES cells appeared to require de novo synthesis of RNA and protein as well as caspase activation. Cyclosporin A, known to be a potent inhibitor of both calcineurin activation and mitochondrial permeability transition pore opening, inhibited CD99-mediated apoptosis, whereas FK-506, a specific calcineurin inhibitor, did not, indicating the induction of CD99-mediated apoptosis through a calcineurin-independent pathway. Furthermore, the dying cells displayed the reduction of mitochondrial transmembrane potential (delta psi m). These results suggest that CD99 engagement induce CsA-inhibitable mitochondrial permeability transition pore opening, followed by a reduction of delta psi m and caspase activation, thereby leading to apoptosis. Based on these results, we suggest the possible involvement of CD99 in the apoptotic processes that occur during nervous system development and also its application in immunotherapeutic trials for ES cases.

12E7 Antigen↗