Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Olfactory neuroblastoma (ONB) is a malignant tumor of the nasal mucosa whose histogenesis is unclear. A relationship to neuroblastoma (NB), a pediatric tumor of the sympathetic nervous system, is based on morphologic similarities and the expression of similar neural antigens. However, the clinical presentation of ONB differs from that of NB, and MYCN amplification characteristic of NB is not observed. We have therefore examined the relationship of this malignancy to other classes of neural tumors. In previous studies, two ONB cell lines demonstrated cytogenetic features and patterns of protooncogene expression suggestive of a relationship to the Ewing sarcoma family of childhood peripheral primitive neuroectodermal tumors (pPNETs). The pPNETs show t(11;22)(q24;q12) or t(21;22)(q22;q12) chromosomal translocations fusing the EWS gene from 22q12 with either the FL11 gene on 11q24 or the ERG gene on 21q22. We therefore analyzed ONBs for the presence of pPNET-associated gene fusions. Both cell lines showed rearrangement of the EWS gene, and fluorescence in situ hybridization (FISH) of each case demonstrated fusion of EWS and FL11 genomic sequences. Moreover, both lines expressed EWS/FL11 fusion transcripts with in-frame junctions between exon 7 of EWS and exon 6 of FL11 as described for pPNETs. We identified similar gene fusions in four of six primary ONB cases. None of the cases expressed tyrosine hydroxylase, a catecholamine biosynthetic enzyme widely expressed in NB. Our studies indicate that ONB is not a NB but is a member of the pPNET family.
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PMID:Olfactory neuroblastoma is a peripheral primitive neuroectodermal tumor related to Ewing sarcoma. 857 10

MYCN gene amplification is strongly correlated with poor prognosis in neuroblastoma (NB), the second most common solid pediatric tumor. However, increased MYCN expression seen in tumors that lack MYCN amplification does not correlate with aggressive clinical behavior. Whereas the MYCN gene spans only 7 kb, the MYCN amplicon has been shown to range in size from 350 kb to more than 1 Mb. Given the large size of the amplicon, it is possible that additional genes are co-amplified in NBs whose expression may contribute to the aggressive phenotype associated with MYCN-amplified tumors. We isolated a cDNA clone from a human NB library that is identical to DDXI, a gene recently reported to be preferentially expressed in two retinoblastoma cell lines that also express high levels of MYCN. DDXI belongs to a family of genes that encode DEAD (Asp-Glu-Ala-Asp) box proteins, putative ATP-dependent RNA helicases implicated in a number of cellular processes involving alterations of RNA secondary structure. We examined the frequency of DDXI amplification in 15 NB cell lines, 1 neuroepithelioma cell line, and 122 NB tumors by Southern blot analyses, and we found that 7 of 10 MYCN-amplified cell lines and 27 of 40 (68%) MYCN-amplified tumors also harbored multiple copies of the DDXI gene. Amplification of DDXI was associated with high levels of DDXI mRNA expression in the NB cell lines and tumors as examined by Northern analysis. Neither DDXI gene amplification nor enhanced expression was observed in tumors or cell lines that lacked MYCN amplification. Because RNA helicases play important roles in both post-transcriptional and translational gene regulation, high levels of DDXI expression consequent to genomic amplification may contribute to the malignant phenotype of a subset of NBs.
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PMID:Co-amplification and concomitant high levels of expression of a DEAD box gene with MYCN in human neuroblastoma. 858 36

Childhood neuroblastoma tumours of the sympathetic nervous system show a remarkable clinical heterogeneity ranging from spontaneous regression to unfavourable outcome despite intensive therapy. Favourable neuroblastomas often express high levels of trkA mRNA, encoding the tyrosine kinase receptor for nerve growth factor. We have investigated mRNA expression for the neurotrophin receptor trkC in 23 primary neuroblastomas using a sensitive RNAase protection assay. TrkC expression was detected in 19 of these tumours at highly variable levels with a 300-fold difference between the highest and lowest values. Significantly higher levels of trkC mRNA were found in tumours from patients with favourable features such as low age (P < 0.012), favourable tumour stage (P < 0.012) and favourable prognosis (P < 0.05). Children with intermediate or high trkC mRNA expression had better prognosis compared with those with low or undetectable levels (83.3% vs 20%, P = 0.005). Further characterisation of trkC mRNA expression by reverse transcriptase-polymerase chain reaction (RT-PCR) showed that mRNA encoding the full-length cytoplasmic tyrosine kinase domain of the receptor was only expressed in a subset of favourable tumours. These data show that favourable neuroblastomas may express the full trkC receptor while advanced tumours, in particular MYCN-amplified neuroblastoma, seem to either express no trkC or truncated trkC receptors of as yet unknown biological function. These data are suggestive of a role for trkC and its preferred ligand neutotrophin-3, NT-3, in neuroblastoma differentiation and/or regression.
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PMID:Expression of mRNA for the neurotrophin receptor trkC in neuroblastomas with favourable tumour stage and good prognosis. 879 81

A DEAD box gene (DDX1) characterized by a motif with a putative RNA helicase was found at elevated levels, with multiple copies, in a neuroblastoma and in some retinoblastoma cell lines in which the MYCN gene was amplified. The present study was aimed at determining whether amplification of the DDX1 gene is critical for human neuroblastomas exhibiting MYCN gene amplification. Extended DNA panels of tumors and cell lines revealed amplification of the DDX1 gene in approximately half of the specimens exhibiting MYCN gene amplification, which is in good agreement with a finding reported recently. Because its profile was similar to that of the cDNA marker G21 and another flanking DNA marker, clone 8, both of which localize outside the core of the amplicon of the MYCN gene, we noted that we could localize the DDX1 gene in relation to the MYCN gene. Utilizing pulsed-field gel electrophoresis according to a method based on the combinatorial alignment of multiple single digests and a 5.5-megabase map surrounding the MYCN locus, we mapped the DDX1 gene within a 100 kb region about 400 kb upstream from the MYCN gene, where G21 is localized. Further hybridization experiments with both genes, complete sequencing of G21, and its comparison with that of the DDX1 gene eventually confirmed that the DDX1 gene is identical to G21. G21 is a cDNA clone isolated by differential screening of a library from a neuroblastoma cell line, IMR-32, but its function has not yet been identified. Coamplification of the DDX1 gene with the MYCN gene is a consequence of the segregation of continuous DNA stretches spanning both loci during the amplification process.
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PMID:Amplification of a DEAD box gene (DDX1) with the MYCN gene in neuroblastomas as a result of cosegregation of sequences flanking the MYCN locus. 883 77

Human neuroblastoma cells frequently show amplification of the oncogene MYCN, which maps to 2p24. Previous studies have localized the DEAD box motif gene DDX1 to the same chromosome band and demonstrated coamplification of DDX1 and MYCN in two retinoblastoma cell lines. Recently, a high frequency of coamplification of DDX1 and MYCN has been shown in human neuroblastoma cells. We have determined the physical distance between the two genes by pulsed field gel electrophoresis in normal tissue and have found that DDX1 maps to a position at a maximum distance of 400 kbp 5' to MYCN. Two neuroblastoma cell lines with coamplification of DDX1/MYCN showed a similar topographic relationship of the two genes. In contrast, in two cell lines with high copy number, the DDX1 gene was not present in all amplified units recognized by MYCN and had changed its position in the amplified DNA relative to MYCN from 5' to 3', presumably by rearrangement during the amplification process. Our data show that the high frequency of DDX1 coamplification is due to its close physical distance to MYCN. Although amplification has resulted in an elevated expression of DDX1 the significance of overexpression for neuroblastoma remains unclear.
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PMID:The DDX1 gene maps within 400 kbp 5' to MYCN and is frequently coamplified in human neuroblastoma. 883 78

The variety of tumor-specific cytogenetic and genetic alterations among small round cell tumors (Ewing family of tumors, rhabdomyosarcoma, neuroblastoma, and lymphoma) increases the possibility of genotypic diagnosis of them. In Ewing's sarcoma and related peripheral primitive neuroectodermal tumors, a (11;22)(q24;q12) translocation is associated with hybrid transcripts of the EWS gene with the FLIl gene. In alveolar rhabdomyosarcoma, a (2;13)(q35;qt4) translocation is associated with a chimeric gene between PAX3 and FKHR. Specific genetic alterations of the short arm of chromosome 1 and amplification of the MYCN gene are diagnostically useful in neuroblastomas as the immunoglobulin or T-cell receptor gene rearrangements and chromosome translocations in lymphomas. Thus, cytogenetics and genetics provide an essential adjunct to diagnostic surgical pathology in the case of small round cell tumors, which often present substantial diagnostic challenges. Likewise, in vitro culture studies represent another approach in determining histogenetic origin, novel genes, novel mechanisms of gene dysregulation, and the biological characteristics of small round cell tumors.
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PMID:Cytogenetics and tissue culture of small round cell tumors of bone and soft tissue. 887 8

One of the most important prognostic factors in neuroblastoma is amplification of the MYCN gene, which is strongly associated with advanced stages of disease and a poor prognosis. Although the MYCN amplicon sometimes spans more than 1 Mb, no other consistently expressed sequences from the MYCN amplicon have been reported. However, DDX1, a gene encoding a DEAD box protein, was recently mapped to chromosome 2p24 and is frequently co-amplified with MYCN. Therefore, we performed genomic mapping with YACs to determine the physical relationship between DDX1 and MYCN, and whether DDX1 was contained within the core region of amplification. Based on YAC restriction mapping and content analysis, DDX1 maps 340 kb 5' of MYCN, outside the core domain of consistent amplification. Interestingly, we also determined by sequence analysis and detailed restriction mapping that G21, previously isolated as a 'neuroblastoma-specific' cDNA clone from an MYCN amplicon, is a partial cDNA of DDX1. Our data confirm that DDX1 is amplified in some but not all MYCN-amplified tumors, and that it is rearranged in other cases. This suggests that the co-amplification of DDX1 is due to its proximity to MYCN.
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PMID:Physical mapping of the DDX1 gene to 340 kb 5' of MYCN. 887 96

Human neuroblastoma (NB) is characterized genetically by deletions of the short arm of chromosome I and by MYCN amplification. Loss of heterozygosity (LOH) has been found frequently for region 1p36. We have studied restriction fragment length polymorphisms (RFLPs) by using anonymous and hypervariable region (HVR) sequences to demonstrate LOH for 1p loci in 50 Italian neuroblastoma patients. Twelve cases (25%) showed LOH at one or more loci. Locus D1S94 was the most frequently involved (8/12 cases with deletion; 67%). MYCN amplification was observed in 20% of the patients. We also studied the allelic distribution in the constitutional DNA of neuroblastoma patients and of healthy Italian subjects for loci D1S112 and D1S94. A significantly (P = 0.01) different allele frequency was detected in the two groups at locus D1S94, but not at D1S112. Furthermore, the NB population was not in Hardy-Weinberg equilibrium at the former locus. This new observation suggests the existence of an allelotype associated with the susceptibility to neuroblastoma.
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PMID:Peculiar allelotype associated with susceptibility to neuroblastoma. 888 8

Neuroblastoma behavior is variable and outcome partially depends on genetic factors. However, tumors that lack high-risk factors such as MYCN amplification or 1p deletion may progress, possibly due to other genetic aberrations. Comparative genomic hybridization summarizes DNA copy number abnormalities in a tumor by mapping them to their positions on normal metaphase chromosomes. We analyzed 29 tumors from nearly equal proportions of children with stage I, II, III, IV, and IV-S disease by comparative genomic hybridization. We found two classes of copy number abnormalities: whole chromosome and partial chromosome. Whole chromosome losses were frequent at 11, 14, and X. The most frequent partial chromosome losses were on 1p and 11q. Gains were most frequent on chromosome 17 (72% of cases). The two patterns of gain for this chromosome were whole 17 gain and 17q gain, with 17q21-qter as a minimal common region of gain. Other common gains were on chromosomes 7, 6, and 18. High level amplifications were detected at 2p23-25 (MYCN region), at 4q33-35, and at 6p11-22. Chromosome 17q gains were associated with 1p and/or 11q deletions and advanced stage. The high frequency of chromosome 17 gain and its association with bad prognostic factors suggest an important role for this chromosome in the development of neuroblastoma.
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PMID:Gain of chromosome 17 is the most frequent abnormality detected in neuroblastoma by comparative genomic hybridization. 900 25

An experimental model of advanced human neuroblastoma, IGR-N-91, which is able to disseminate in the nude mouse, has been described. The present study was designed to ascertain which cell population from the IGR-N-91 primary tumour actually disseminates throughout the animals. In s.c. IGR-N-91 tumour xenografts, 3 areas, called pearly, vascularized and haemorrhagic, depending on the presence of blood vessels and haemorrhagic suffusions, were consistently observed and independently resected. Molecular analysis of tumour materials revealed a significant increase in MYCN and max gene transcript levels in the haemorrhagic area, as compared with the pearly and vascularized areas. Given the growth kinetics observed both in vitro and in vivo, and the DNA flow-cytometry profiles of tumour cells obtained from the haemorrhagic area, this transcriptional increase did not appear to be associated with enhanced proliferation. In this area of the tumours, multidrug-resistance-related genes, i.e., MDRI, MRP, GST-pi and topoisomerase II alpha were activated concomitantly with MYCN and max genes. The same observations were made, except for the topoisomerase-II alpha gene, when sub-lines derived from metastases were compared with that derived from the primary tumour. These data demonstrate that over-expression of several genes determining the multi-drug-resistance phenotype precedes the metastatic spread of IGR-N-91 NB tumour cells in the nude mouse. Data also suggest that the cell sub-population exhibiting this pleiotropic over-expression within the primary tumour undergoes selection during metastatic dissemination.
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PMID:Pleiotropic over-expression of multidrug-resistance-related genes is correlated to MYCN and max mRNA accumulation during tumour progression in the IGR-N-91 human neuroblastoma model. 903 51


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