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PubMed2001

Insulin production in a neuroectodermal tumor that expresses islet factor-1, but not pancreatic-duodenal homeobox 1.

We studied a 60-yr-old female with a brain tumor who showed severe symptoms of hypoglycemia (plasma glucose, 2.2 mmol/L) and hyperinsulinemia (1.28 nmol/L) after radiotherapy. The cystic brain tumor contained proinsulin and insulin at concentrations of 13.6 and 1.22 nmol/L, respectively. Immunohistochemical studies showed the tumor cells were ectodermal in origin but not endodermal, based on three diagnostic features of neuroectodermal tumors 1) pseudorosette formation noted under light microscopy, 2) finding of a small number of dense core neurosecretory granules on electron microscopy, and 3) positive immunostaining for both neuronal specific enolase and protein gene product 9.5. These cells also expressed the transcription factor, neurogenin-3, NeuroD/beta 2, and islet factor I, which are believed to be transcription factors in neuroectoderm as well as in pancreatic islet cells, but not pancreatic-duodenal homeobox 1, Pax4, or Nkx2.2. In addition, they did not express glucagon, somatostatin, or glucagon-like peptide-1. Our results show the presence of proinsulin in an ectoderm cell brain tumor that does not express the homeobox gene, pancreatic-duodenal homeobox 1, but expresses other transcription factors, i.e. neurogenin3, NeuroD/beta 2, and islet factor-1, which are related to insulin gene expression in the brain tumor.

Antigens, Differentiation↗
PubMed2001

Diffusion-weighted imaging and fluid attenuated inversion recovery imaging in the evaluation of primitive neuroectodermal tumors.

The aim of our study was to determine whether fluid-attenuated inversion recovery (FLAIR) imaging and diffusion-weighted imaging (DWI) would be helpful in characterizing primitive neuroectodermal tumors (PNET) from other pediatric brain tumors. We expected that the compact cellular nature and the relatively small extracellular space of this tumor would affect the signal intensity on both pulse sequences relative to the more sparsely cellular glial tumors that have larger extracellular spaces. Eighteen pediatric patients with PNET were examined on a 1.5 T MRI with routine imaging plus FLAIR and compared with 28 patients with nonPNET. DWI was also performed in 7 PNET and 18 non-PNET. Seventyeight percent of PNET were isointense to gray matter on FLAIR while 82% of non-PNET were hyperintense and only one was isointense (3%). Diffusion was abnormally restricted in all 7 PNET examined (100%) but was restricted in non-PNET in only 1 out of 18 (6%) patients who had DWI. The differences in the histologic architecture between PNET and non-PNET are reflected in both FLAIR imaging and in DWI.

Adolescent↗
PubMed2001

Ewing sarcoma and sinonasal neuroectodermal tumors as second malignant tumors after retinoblastoma and other neoplasms.

BACKGROUND: Excesses of various childhood cancers have been reported after retinoblastoma, including a trickle of Ewing sarcoma (ES) and perhaps histologically similar olfactory neuroblastoma, both of which are neural tumors. To update and advance this information, case reports were sought by an extensive review of the literature. PROCEDURE: The search was made through the use of PubMed, and the Web of Science (Citation Index Expanded), keying on primary references. Three sinonasal cancers diagnosed as ES were immunohistochemically stained for MIC-2 protein (positive in ES). RESULTS: Retinoblastoma occurred before ES in ten cases (seven bilateral). In four others, retinoblastoma (three bilateral) developed before sinonasal neural tumors (poorly differentiated). ES also occurred after 14 cancers other than retinoblastoma (five lymphomas, four leukemias, and one each of five miscellaneous cancers). The predominance of retinoblastoma prior to ES differs markedly from the low-frequency of retinoblastoma among childhood cancers in the general population. On the contrary, cancers other than retinoblastoma were proportionate to those in the general population. Previously, retinoblastoma followed by excesses of osteosarcoma and soft tissue sarcomas has been attributed to the action of the inherited RB-1 gene. The sinonasal tumors stained negative for MIC-2 protein. CONCLUSIONS: Heritable retinoblastoma may predispose to ES and perhaps to a subset of poorly differentiated neuroectodermal tumors in the sinonasal region that may be related to olfactory neuroblastoma.

Adolescent↗
PubMed2002

Upregulation of Ku expression in human neuroectodermal tumor cells after retroviral DNA integration.

OBJECTIVE: To examine the expression of DNA-dependent protein kinase (DNA-PK); including DNA-PKcs, Ku70 and Ku80 in human neuroectodermal tumor cells with or without retroviral DNA integration. METHODS: RT-PCR assay was used to examine the transcript of DNA-PK. Western blot and immunocytochemistry assays were used to examine the protein level of DNA-PK. RESULTS: The expression of DNA-PKcs was similar in the cells with or without retroviral DNA integration, but the expression of Ku (both mRNA and protein for Ku70 and only protein for Ku80) was higher in cells with retroviral DNA integration than in cells without retroviral DNA integration. CONCLUSION: The expression of Ku but not the expression of DNA-PKcs is induced by retroviral DNA integration. Ku70 may play an important role in the regulation of Ku function in response to retroviral DNA integration.

Antigens, Nuclear↗
PubMed1997

High-resolution deletion mapping of chromosome arm 17p in childhood primitive neuroectodermal tumors reveals a common chromosomal disruption within the Smith-Magenis region, an unstable region in chromosome band 17p11.2.

Loss of heterozygosity (LOH) on chromosome arm 17p is the most common genetic aberration in childhood primitive neuroectodermal tumors (PNETs). To determine the frequency and extent of 17p deletions, 29 loci on 17p were investigated in 24 tumors by using restriction fragment length polymorphism (RFLP) and microsatellite analysis. LOH on 17p was found in 9 of 24 tumors. In all tumors with LOH, a continuous stretch from the telomere to chromosome band 17p11.2 was completely deleted, and no interstitial or terminal small-scale deletions were detected in the remaining 15 tumors. In four tumors with LOH on 17p, the chromosomal breakpoint was located between D17S953 and D17S805. To identify this deletion breakpoint on the cytogenetic map of chromosome 17 and to exclude uniparental disomy, we verified our data by using fluorescence in situ hybridization (FISH) analyses. By using two yeast artificial chromosome (YAC) clones that were positive for D17S689 and D17S953, the same breakpoint was confirmed in two specimens of cerebrospinal fluid (CSF) metastases by using FISH on interphase preparations. We demonstrate that, in most childhood PNETs with LOH on 17p, the breakpoint is close to, but not within, the centromere. It varies, and it occurs predominantly between the two markers D17S689 and D17S953, which is an unstable chromosomal region that is deleted or duplicated in the Smith-Magenis syndrome. Because LOH of 17p is associated with the formation of isochromosome 17q in the majority of PNETs, this study provides entry points to determine the molecular nature of this phenomenon.

Adolescent↗
PubMed2006

Phase II study of oxaliplatin in children with recurrent or refractory medulloblastoma, supratentorial primitive neuroectodermal tumors, and atypical teratoid rhabdoid tumors: a pediatric brain tumor consortium study.

BACKGROUND: An open-label Phase II study of oxaliplatin was conducted to evaluate its safety and efficacy in children with recurrent or refractory medulloblastoma (MB), supratentorial primitive neuroectodermal tumors (SPNET), and atypical teratoid rhabdoid tumor (ATRT). METHODS: Patients were stratified as follows: stratum IA, first recurrence MB with measurable disease; IB, recurrent MB with only cerebral spinal fluid (CSF) positivity or linear leptomeningeal disease (LLD); IC, MB > or =second recurrence; stratum II, recurrent SPNET; stratum III, recurrent ATRT. Patients received oxaliplatin, 130 mg/m(2) intravenously over 2 hours every 3 weeks. The primary objective was to estimate the sustained response rate in stratum 1A. Plasma ultrafiltrate platinum pharmacokinetics were evaluated. RESULTS: A total of 43 patients with a median age of 8.5 years (range, 0.6-18.9 years) were enrolled. In stratum 1A, 2 of 15 had partial responses (PRs, 1 sustained PR). No responses were observed in other strata. The most frequent Grade 3 and 4 toxicities included thrombocytopenia (25.6%), neutropenia (16.3%), leukopenia (12%), increase in serum alanine transaminase (ALT) (7%), vomiting (4.7%), and sensory neuropathy (4.7%). No severe ototoxicity or nephrotoxicity was reported. Plasma ultrafiltrate platinum pharmacokinetic parameters were similar to adults, with a median clearance of 12.2 L/hr (range, 4.4-30 L/hr) and median area under the curve (AUC(0-infinity)) of 9.4 microg/mL/hr (range, 6.2-13.9 microg/mL/hr). CONCLUSIONS: Oxaliplatin was well tolerated in children but has limited activity in children with recurrent CNS embryonal tumors previously treated with platinum compounds.

Adolescent↗
PubMed1991

Cytogenetic analysis of primitive neuroectodermal tumors. Absence of the t(11;22) in two of three cases and a review of the literature.

Cytogenetic analyses on direct and short-term cultures from three peripheral primitive neuroectodermal tumors (PNET) showed only one tumor with the t(11;22)(q24;q12), a translocation reported as characteristic of this tumor type. A second tumor contained rearrangements including apparent deletions of chromosomes 11 and 22 between bands 11q21 and 11qter and between bands 22q11.2 and 22qter, respectively. A third tumor contained two normal copies of 11q but appeared to be monosomic for 22. We consider these findings in light of a survey of the PNET literature.

Adolescent↗
PubMed2005

Untreated pediatric primitive neuroectodermal tumor in vivo: quantitation of taurine with MR spectroscopy.

PURPOSE: To retrospectively investigate whether quantitation of taurine (Tau) concentrations with proton magnetic resonance (MR) spectroscopy in vivo improves the differentiation of primitive neuroectodermal tumors (PNET) from other common brain tumors in pediatric patients. MATERIALS AND METHODS: The institutional review board approved this review of clinical data; it was not necessary to obtain parental consent. This study was HIPAA compliant. Single-voxel proton spectroscopy was added to the preoperative MR imaging work-up of 29 patients (12 boys and 17 girls; mean age, 6.5 years +/- 3.5) with untreated brain tumors; 13 had PNETs, and 16 had other tumors. Absolute concentrations (measured in millimoles per kilogram of brain tissue) of metabolites of the proton spectrum were determined. Student t tests were used for statistical comparisons. RESULTS: Elevated absolute Tau concentration proved to be the most significant metabolite in the differentiation of PNETs from other tumors (6.09 mmol/kg +/- 2.24 vs 0.76 mmol/kg +/- 0.95, P < .001). PNETs also exhibited a higher ratio of Tau relative to choline (1.21 +/- 0.48 vs 0.28 +/- 0.39, P < .001), a higher ratio of Tau relative to creatine (1.28 +/- 0.44 vs 0.38 +/- 0.67, P < .001), a reduced a ratio of N-acetyl-aspartate relative to choline (0.20 +/- 0.20 vs 0.79 +/- 0.56, P < .001), and an increased choline concentration (5.30 mmol/kg +/- 1.64 vs 3.08 mmol/kg +/- 2.53, P < .05). Tau concentrations ranged from 2.62 to 11.15 mmol/kg in individual patients with a PNET. CONCLUSION: Single-voxel quantitative (1)H MR spectroscopy performed in patients with untreated pediatric brain tumors showed that the Tau concentration was significantly elevated in PNETs and was useful in the differentiation of PNETs from other tumors.

Child↗
PubMedDate not supplied

Primary intraspinal primitive neuroectodermal tumor treated with autologous stem cell transplantation: case report and review of the literature.

The authors describe the case of a 19-year-old female patient with a primary primitive neuroectodermal tumor (PNET) of the thoraco-lumbar spinal cord, who presented with acute urinary retention and back pain for 2 months. Magnetic resonance imaging revealed an intradural extramedullary tumor, 6.5 cm long, in the region of the conus medullaris. Histological examination disclosed a small round cell tumor with immunohistochemical characteristics of a peripheral PNET. Metastatic workup showed no evidence of an intracranial tumor or metastases outside the neuroaxis. The patient received multidisciplinary treatment, including surgical excision, irradiation of the entire cranio-spinal axis, and high-dose chemotherapy with autologous stem cell rescue. Presently, 24 months after diagnosis, the patient remains in complete remission.

Adult↗
PubMed2003

Constitutional t(16;22)(p13.3;q11.2 approximately 12) in a primitive neuroectodermal tumor of the pineal region.

Constitutional chromosome anomalies are known to determine an increased risk of malignancy in certain disorders. We report the case of a 6-month-old female with a primitive neuroectodermal tumor (PNET) of the pineal region and a constitutional reciprocal translocation t(16;22)(p13.3;q11.2 approximately 12). The clustering of cancer chromosome breakpoints to specific chromosome regions is a well-documented phenomenon, with breakpoints on chromosome 22q11.2 approximately 12 having been identified in several subtypes of small round cell tumors. The finding of a 22q11.2 approximately 12 breakpoint in this patient suggests this constitutional translocation may somehow have predisposed the patient to the development of the tumor.

Brain Neoplasms↗
PubMed2002

Antitumoral effect of irinotecan (CPT-11) on an experimental model of malignant neuroectodermal tumor.

Irinotecan (CPT-11) is a topoisomerase I inhibitor with antitumor activity on a wide variety of neoplasms in several preclinical studies, but it showed poor efficacy in patients with nervous system tumors. We have carried out an experimental study in order to evaluate the effect of CPT-11 on the growth of a subcutaneously implanted malignant neuroectodermal tumor, after administration by different routes. The results showed that CPT-11 administration by intraperitoneal injections (at dose 10 mg/kg, 5 days per week, for 2 weeks, followed by 7-days rest period--one course--to a total of two courses) had no significant antitumor effect. Nevertheless, continuous infusion by intraperitoneal osmotic minipump over 28 days (at an infusion rate of 4.4 microg/h) showed a significant delay in tumor growth in 4 weeks of the implantation. The best antitumor effects were observed after CPT-11 intratumoral administration (at dose of 5 mg/kg, 5 days per week, for 2 weeks, followed by 7-days rest period, to a total of three courses) reaching tumor regression in the treated animals. These results suggest the utility of CPT-11, by means of intralesional administration, on malignant tumors of the nervous system.

Animals↗
PubMed1993

Primitive neuroectodermal tumor (PNET) extending into the cerebellopontine angle: case report.

The most common primary tumors of the cerebellopontine angle are growths of the 8th cranial nerve. The occurrence of other tumors in this area is very rare and may cause neuroradiological misinterpretation. We report the findings in a 37-year-old male patient suffering from a primitive neuroectodermal tumor (PNET) extending from the latero-basilar cerebellar hemisphere into the cerebellopontine angle (CPA) and causing cerebellar dysfunction as well as symptoms of typical cerebellopontine angle lesions. Differential diagnosis of tumors found in this area is given as well as a histological description of the tumor along with immunohistochemical findings and aspects of possible prognostic relevance.

Adult↗
PubMed1995

Insulin-induced differentiation and modulation of neuronal thread protein expression in primitive neuroectodermal tumor cells is linked to phosphorylation of insulin receptor substrate-1.

Neuronal thread proteins (NTPs) are a family of developmentally regulated molecules expressed in central nervous system (CNS) neurons and primitive neuroectodermal tumor (PNET) cell lines. NTP gene expression is modulated with DNA synthesis, neuritic sprouting, and neuronal differentiation. The present study explores the mechanism of insulin modulation of NTP gene expression during neuronal differentiation using PNET cell lines of CNS origin. PNET2 cells underwent neuronal differentiation with neurite outgrowth coupled with transient up-regulation of several species of NTP. In contrast, PNET1 cells failed to differentiate in response to insulin stimulation, although insulin receptors were more abundant than in PNET2 cells. Analysis of the insulin-mediated signal transduction pathway demonstrated that the lack of insulin responsiveness in PNET1 cells was primarily caused by impaired insulin-mediated tyrosyl phosphorylation of the insulin receptor substrate-1 (IRS-1). Correspondingly, the association between phosphatidyl-inositol 3 (PI3) kinase and phosphorylated IRS-1 was reduced in PNET1 compared with PNET2 cells. In contrast, the levels of IRS-1 protein were similar in PNET1 and PNET2 cells, and expression of the insulin receptor beta subunit (Ir beta) and insulin-mediated tyrosyl phosphorylation of the Ir beta were greater in PNET1 than PNET2 cells. The findings suggest that insulin effected neuronal differentiation and modulation of NTP gene expression in PNET cells utilizes a signal transduction cascade that requires tyrosyl phosphorylation of IRS-1.

Blotting, Western↗
PubMed2004

Treatment of metastatic Ewing's sarcoma or primitive neuroectodermal tumor of bone: evaluation of combination ifosfamide and etoposide--a Children's Cancer Group and Pediatric Oncology Group study.

PURPOSE: One hundred twenty patients with metastatic Ewing's sarcoma or primitive neuroectodermal tumor (PNET) of bone were entered onto a randomized trial evaluating whether the addition of ifosfamide and etoposide to vincristine, doxorubicin, cyclophosphamide, and dactinomycin improved outcomes. METHODS: Thirty-two patients had metastases to lungs only, 12 patients had metastases to bone marrow or bones only, 64 patients had metastases in multiple sites, and five patients had metastases in other sites; seven patients could not be assessed precisely. Treatment comprised 9 weeks of chemotherapy before local control and 42 weeks of chemotherapy; thereafter, regimen A consisted of vincristine 2 mg/m(2), cyclophosphamide 1,200 mg/m(2), and either doxorubicin 75 mg/m(2) or dactinomycin 1.25 mg/m(2). Regimen B consisted of regimen A alternating every 3 weeks with ifosfamide 1,800 mg/m(2)/d for 5 days and etoposide 100 mg/m(2)/d for 5 days. RESULTS: Patients treated on regimen B did not have significantly better survival than those treated on regimen A. The event-free survival (EFS) and survival (S) at 8 years were 20% (SE, 5%) and 32% (SE, 6%), respectively, for those treated on regimen A and 20% (SE, 6%) and 29% (SE, 6%), respectively, for those treated on regimen B. Patients who had only lung metastases had EFS and S of 32% (SE, 8%) and 41% (SE, 9%), respectively, at 8 years. There were six toxic deaths (5%), four from cardiac toxicity and two from sepsis (four treated on regimen B and two treated on regimen A). Two had second malignant neoplasms. CONCLUSION: Adding ifosfamide and etoposide to standard therapy does not improve outcomes of patients with Ewing's sarcoma or PNET of bone with metastases at diagnosis.

Adolescent↗
PubMed1994

A model for primitive neuroectodermal tumors in transgenic neural transplants harboring the SV40 large T antigen.

Using retrovirus-mediated transfer of the SV40 virus large T antigen into neural transplants, we have observed a high incidence of primitive neuroectodermal tumors (PNET). These neoplasms developed in 8 of 14 (57%) neural grafts after latency periods of 176 to 311 days. Histopathologically, the tumors exhibited features of human PNET such as formation of neuroblastic rosettes and immunocytochemical evidence for neuronal differentiation, synaptogenesis, and focal astrocytic differentiation. All neoplasms showed a striking migratory potential. The presence of the large T gene in the tumors was demonstrated by polymerase chain reaction-mediated amplification of a specific 242 bp segment of large T and DNA sequence analysis. Large T antigen was identified in tissue sections using an immunocytochemical reaction with the monoclonal antibody Pab 108. Cell lines were established from several tumors and subjected to G418 selection. Secondary tumors induced by intracerebral transplantation of these cells retained the characteristic morphological and immunocytochemical properties of PNETs. These experiments demonstrate a considerable transforming potential of SV40 large T antigen for neural precursor cells. The long latency period suggests that neoplastic transformation initiated by the large T gene requires additional spontaneous mutations of cooperating cellular genes. Because the mechanism of transformation by large T antigen appears to involve complex formation with and inactivation of cellular tumor suppressor gene products, these cell lines may serve as an interesting tool to search for novel neural tumor suppressor genes.

Animals↗
PubMed1981

Melanotic neuroectodermal tumor of infancy: an ultrastructural study, literature review, and reevaluation.

Two cases of melanotic neuroectodermal tumor of infancy were examined by electron microscopy and an extensive review of the literature was performed. Ultrastructural examination revealed several features not previously described for this lesion. Three different types of melanin granule formation were observed, many cells had a single cilium, and cell junctions of the "close" or "modified-tight" type were seen, but no desmosomes were found. The morphologic data were consistent with the concept that the tumor arises from neural crest cells. The review of the literature indicated that there have been 158 reported cases of this lesion, including the two reported here. There were five cases of malignant tumor reported for a rate of 3.2%. This rate of malignancy is very high in view of the fact that the tumor has been described as universally benign. The significance of this finding is discussed with regard to melanin-producing lesions of the oral cavity.

Female↗
PubMed1981

The melanotic neuroectodermal tumor of infancy. Report of two cases and review of the literature.

The melanotic neuroectodermal tumor of infancy (MNTI) is a rare childhood neoplasm with an alarming but classical clinical presentation. It appears as a rapidly enlarging mass in the jaws of skull of infants and unless MNTI is considered in the differential diagnosis, the lesion can easily be mistaken for a malignant neoplasm. Although possessing an aggressive growth rate and radiographic appearance, the MNTI almost always behaves in a benign fashion and can be treated with local excision. However, recent reports of malignant behavior as well as of occasional recurrences make close follow-up important. Approximately 139 cases of the MNTI have been reviewed and tabulated with respect to age at discovery, sex, tumor location, length of follow-up, and whether recurrence occurred, 2 additional cases, 1 of which was in the mandible, are presented along with theories of origin and recommended therapy.

Diagnosis, Differential↗