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Query: UMLS:C0027819 (neuroblastoma)
 27,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

BACKGROUND AND METHODS. Genetic analysis of tumor tissue has provided considerable insight into mechanisms of malignant transformation and progression. Neuroblastomas have been studied by cytogenetics, flow cytometry, and molecular genetic techniques, and these studies have identified several specific abnormalities that allow subclassification of these tumors into genetic/clinical subtypes. RESULTS AND DISCUSSION. Four genetic abnormalities have been identified that are characteristic of certain neuroblastomas. These include: (1) loss of heterozygosity (LOH) for the short arm of chromosome 1, including band 1p36; (2) amplification of the N-myc protooncogene; (3) hyperdiploidy, or near triploidy; and (4) defects in expression or function of the nerve growth factor receptor (NGFR). Abnormalities of the NGFR are found in virtually all neuroblastoma cell lines, and some primary tumors. The latter have not been studied extensively. Hyperdiploidy is associated with lower stages of disease and with a favorable outcome in infants. LOH for chromomors. The latter have not been studied extensively. Hyperdiploidy is associated with lower stages of disease and with a favorable outcome in infants. LOH for chromosome 1, band p36, and N-myc amplification are more common in patients older than 1 year of age with advanced stages of disease. The latter two genetic abnormalities may be related, and LOH for 1p36 may precede the development of amplification. When these abnormalities are combined with assessment of DNA content, three distinct genetic subsets of neuroblastomas can be identified. The first is characterized by a hyperdiploid or near-triploid modal karyotype, with few if any cytogenetic rearrangements. These patients generally are younger than 1 year of age with localized disease and a good prognosis. The second has a near-diploid karyotype, with no consistent abnormality identified currently. These patients generally are older with more advanced stages of disease that progress slowly and are often fatal. The third group has a near-diploid or tetraploid karyotype, with deletions or LOH for 1p36, amplification of N-myc, or both. These patients generally are older with advanced stages of disease that rapidly are progressive. Thus, genetic analysis of neuroblastoma cells provides information that has prognostic significance and can direct a more appropriate choice of treatment.
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PMID:Neuroblastoma. Effect of genetic factors on prognosis and treatment. 132 79

Neuroblastomas are heterogeneous in terms of both their genotype and their clinical behavior. Recent studies suggest that these two features are related, and that the genotype frequently is predictive of response to treatment or the outcome of the patient. The genetic abnormalities that are characteristic of certain neuroblastomas include: (a) loss of heterozygosity (LOH) for the short arm of chromosome 1, including band 1p36; (b) amplification of the N-myc protooncogene; and (c) hyperdiploidy, or near-triploidy, determined either by flow cytometry or by karyotype. Hyperdiploidy is associated with lower stages of the tumor and with a favorable outcome in infants. However, LOH for chromosome 1 (band p36) and N-myc amplification are more common in patients over 1 year of age who have advanced stages of the tumor. Based on analysis of neuroblastomas for these genetic abnormalities, three distinct genetic subsets can be identified. The first is characterized by a hyperdiploid or near-triploid modal karyotype, with few, if any, cytogenetic rearrangements. These patients are generally less than 1 year of age, they have localized tumors, and have a good prognosis. The second genetic subset has a near-diploid karyotype, but with no consistent abnormality identified to date. They are generally older patients with tumors in the more advanced stages that progress slowly and are often fatal. Patients in the third group of genetic abnormalities have a near-diploid or tetraploid karyotype, with deletions or loss of heterozygosity for 1p36, amplification of N-myc, or both. These patients are generally older; they have advanced stage tumors that are rapidly progressive.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Molecular basis of clinical heterogeneity in neuroblastoma. 135 15

Chromosome abnormalities found in pediatric solid tumors include deletions, translocations, homogeneously staining regions (hsr)/double minutes (dms), and ploidy abnormalities. The discovery of a 13q14 deletion found in lymphocytes of patients with retinoblastoma and developmental delay has led to the cloning of the retinoblastoma gene. Likewise the discovery of an 11p13 deletion in lymphocytes of patients with Wilms' tumor and aniridia has led to the cloning of the Wilms' tumor gene. Chromosome deletions found in tumor cells are considered to play a role on the homologous deletion of cancer suppressor genes. Recently, various translocations have been found mostly in soft tissue sarcomas; i.e. t(11;22) in Ewing's sarcoma, t(2;13) in alveolar rhabdomyosarcoma, t(3;8) in pleomorphic adenoma, t(3;12) in lipoma, t(12;16) in liposarcoma, t(12;14) in leiomyosarcoma, and t(X;18) in synovial sarcoma. These translocations provide important information on the difficult diagnosis of soft tissue sarcomas, and on the selection of chemotherapy protocol. Tumor cells in advanced stage neuroblastomas often show hsr/dms, in which N-myc amplification occurs. While near triploidy was regularly found in early-stage neuroblastomas, near-diploidy or near-tetraploidy was usually found in advanced stage tumors. Among various prognostic factors, N-myc copy numbers and tumor cell ploidies had the largest influence on the prognosis of neuroblastoma patients. Cytogenetic and molecular genetic analyses on tumor cells are becoming increasingly important for the diagnosis of pediatric solid tumors, and the prediction of the patients' prognosis.
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PMID:[Cytogenetics in pediatric solid tumors]. 217 98

The relationship between cytogenetic findings and prognosis in 51 pediatric patients with neuroblastoma is described. Patients were classified into the following four groups based on karyotypic findings: (1) near diploidy, 42 to 47 chromosomes (n = 11); (2) hyperdiploidy, 50 to 56 chromosomes (n = 4); (3) near triploidy, 60 to 77 chromosomes (n = 33); and (4) hypotetraploidy, 80 to 83 chromosomes (n = 3). Patients with near diploid or hypotetraploid karyotypes also had several structural abnormalities including marker chromosome 1, with or without double minutes (DM) or homogeneously staining regions (HSR). Most of these patients were 1 year of age or older and had advanced tumors. The patients who were in the hyperdiploid or near triploid category had few structural abnormalities; all of them, except one, were younger than 1 year of age, had localized tumors, and are long-term, disease-free survivors. Kaplan-Meier analysis of survival rates disclosed a significant difference favoring the latter group (P less than 0.001). N-myc gene amplification was found in five patients of the former group but in no patients of the latter group. The presence or absence of DM or HSR in the former group had no statistically demonstrable effect on survival. However, the presence of marker chromosome 1 appears to indicate a poor prognosis. Five patients with Stage IV-S disease had near triploid abnormalities similar to findings in patients with localized tumors. We propose that localized and Stage IV-S neuroblastomas can be classified as one disease category, and that patients with near diploid or hypotetraploid karyotypes are clinically distinct from those having hyperdiploid or near triploid karyotypes. We consider that chromosomal pattern is a more influential prognostic factor than age, disease stage, or N-myc gene amplification.
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PMID:Cytogenetic findings and prognosis in neuroblastoma with emphasis on marker chromosome 1. 291 Apr 10

We performed chromosome analysis of 15 neuroblastomas found by mass screening using a vanillymandelic acid spot test. We found near triploid chromosome abnormalities, ranging from 60 to 77 chromosomes, in the tumor cells from 14 patients, and hyperdiploidy with the mode of 50 in cells from one. A structural abnormality was observed in only one patient. We did not find a marker chromosome 1, homogeneously staining region, or double minutes, which have been previously reported in advanced neuroblastomas or in cell lines. All of our patients were completely free of disease 4 to 32 months after diagnosis. We consider that patients with hyperdiploidy or near triploidy are different from those with marker chromosome 1, homogeneously staining region, or double minutes and may constitute a subgroup with a good prognosis in childhood neuroblastoma.
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PMID:Chromosome findings and prognosis in 15 patients with neuroblastoma found by VMA mass screening. 335 79

Neuroblastoma (NB) is a heterogeneous disease. The clinical course may range from spontaneous regression and maturation to very aggressive behaviour. Stage 4s is a unique subcategory of NB, generally associated with good prognosis, despite skin and/or liver involvement and the frequent presence of tumour cells in the bone marrow. Another type of NB is the locally invasive tumour without bone and bone marrow involvement which can also have a good prognosis, irrespective of lymph node involvement. Unfortunately, there is only limited biological information on such tumours which have not been treated with cytotoxic therapy despite lymph node involvement, residual tumour mass after surgery and/or bone marrow infiltration. In order to find specific genetic changes common to NBs with a benign clinical course, we studied the genetic abnormalities of these tumours and compared them with highly aggressive tumours. We analysed a series of 54 localised and stage 4s tumours by means of in situ hybridisation performed on fresh cells or on paraffin embedded tissues. In addition, we performed classical cytogenetics, Southern blotting and PCR analysis on fresh tumour tissue. The majority of patients had been treated with surgery alone, and in a number of patients tumour resection was incomplete. Deletions at 1p36 and amplifications of the MYCN oncogene were absent, and diploidy or tetraploidy were not seen in any case, with residual localised tumours possessing a favourable outcome. Unexpectedly, one patient with a tetraploid 4s tumour without any genetic structural changes not receiving any cytotoxic treatment, did well. Interestingly, this genetic spectrum contrasted with that of progressing tumours, in which most had genetic aberrations, the deletion at 1p36 being the most common event. These data, although limited, suggest that an intact 1p36 (recognised by D1Z2), the absence of MYCN amplification and near-triploidy (at least in localised tumours), represent prerequisites for spontaneous regression and/or maturation.
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PMID:Regression and progression in neuroblastoma. Does genetics predict tumour behaviour? 757 55

Neuroblastoma is a neural crest-derived embryonal tumour of the postganglionic sympathetic nervous system and a disease with several different chromosomal gains and losses, which include MYCN-amplified neuroblastoma on chromosome 2, deletions of parts of the chromosomes 1p and 11q, gain of parts of 17q and triploidy. Recently, activating mutations of the ALK (Anaplastic Lymphoma Kinase) RTK (Receptor Tyrosine Kinase) gene have been described in neuroblastoma. A meta-analysis of neuroblastoma cases revealed that ALK mutations (49 of 709 cases) in relation to genomic subtype were most frequently observed in MYCN amplified tumours (8.9%), correlating with a poor clinical outcome. MYCN proteins target proliferation and apoptotic pathways, and have an important role in the progression of neuroblastoma. Here, we show that both wild-type and gain-of-function mutants in ALK are able to stimulate transcription at the MYCN promoter and initiate mRNA transcription of the MYCN gene in both neuronal and neuroblastoma cell lines. Further, this stimulation of MYCN gene transcription and de novo MYCN protein expression is abrogated by specific ALK inhibitors, such as crizotinib (PF-2341066), NVP-TAE684, and by small interfering RNA to ALK resulting in a decrease in proliferation rate. Finally, co-transfection of ALK gain-of-function mutations together with MYCN leads to an increase in transformation potential. Taken together, our results indicate that ALK signalling regulates initiation of transcription of the MYCN gene providing a possible explanation for the poor clinical outcome observed when MYCN is amplified together with activated ALK.
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PMID:Anaplastic Lymphoma Kinase (ALK) regulates initiation of transcription of MYCN in neuroblastoma cells. 2228 64