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)

The N-myc oncogene has been implicated in the pathogenesis of a number of human tumors, including childhood neuroblastoma and adult small cell lung cancer. We have isolated and characterized complementary DNA clones derived from a transcription unit, N-cym, located on the opposite DNA strand to N-myc, with extensive overlap existing between the 5' ends of the two transcription units. The N-cym gene, which can encode a 109-amino acid protein, is expressed during fetal development, as well as in tumor cell lines containing amplified N-myc loci, where it is expressed at very high levels. Although other examples of overlapping, opposite-strand eukaryotic genes exist, N-myc and N-cym are unique in that they appear to be coregulated in tumor cell lines under basal growth conditions and in response to the differentiating agent retinoic acid. This coregulation suggests that their protein products may be functionally interrelated during normal development and oncogenesis.
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PMID:Isolation and characterization of complementary DNA for N-cym, a gene encoded by the DNA strand opposite to N-myc. 141 2

Oncogene amplification is observed frequently in human cancers, but little is known about the mechanism of gene amplification or the structure of amplified DNA in tumor cells. We have studied the N-myc amplified domain from a representative neuroblastoma cell line, SMS-KAN, and compared the map of the amplicon in this cell line with that seen in normal DNA. The SMS-KAN cell line DNA was cloned into yeast artificial chromosomes (YACs), and clones were identified by screening the YAC library with amplified DNA probes that were obtained previously (B. Zehnbauer, D. Small, G. M. Brodeur, R. Seeger, and B. Vogelstein, Mol. Cell. Biol. 8:522-530, 1988). In addition, YAC clones corresponding to the normal N-myc locus on chromosome 2 were obtained by screening two normal human YAC libraries with these probes, and the restriction maps of the two sets of overlapping YACs were compared. Our results suggest that the amplified domain in this cell line is a approximately 1.2-Mb circular molecule with a head-to-tail configuration, and the physical map of the normal N-myc locus generally is conserved in the amplicon. These results provide a physical map of the amplified domain of a neuroblastoma cell line that has de novo amplification of an oncogene. The head-to-tail organization, the general conservation of the normal physical map in the amplicon, and the extrachromosomal location of the amplified DNA are most consistent with the episome formation-plus-segregation mechanism of gene amplification in these tumors.
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PMID:Isolation and structural analysis of a 1.2-megabase N-myc amplicon from a human neuroblastoma. 144 86

Na(+)-dependent amino isobutyric acid transport by two neuroblastoma cell lines with and without amplification of the oncogene N-myc is studied. Surprisingly, the contribution of system A is greater in the cell line showing no N-myc amplification. Preliminary data support a role for essential tyrosine and cysteine residues in the active center of the carriers, mainly in system A.
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PMID:Na(+)-dependent AIB transport by neuroblastoma cells. 145 99

Between June 1983 and December 1990, cytogenetic analysis was performed on 82 neuroblastoma patients, including 41 patients found by mass screening. The N-myc copy number was determined in 77 of the 82 patients. Patients were classified into three groups: patients found by mass screening (group A) (n = 41), patients found clinically who were under 12 months of age (group B) (n = 12), and patients found clinically who were over 12 months of age (group C) (n = 29). All patients in group A had hyperdiploid (H-2n) or near-triploid (3n) karyotypes; they were all completely free of tumor for 4-84 months after diagnosis, although one patient relapsed and attained complete remission again. Among those in group B, one patient with a stage 4 tumor had a near-diploid Karyotype (2n) and N-myc amplification, and died 18 months after diagnosis. Another patient aged 2 days with a stage 4S tumor had near-diploid karyotype and N-myc amplification, and died 9 months after diagnosis. Tumors in the remaining 18 patients in group B had hyperdiploid or near-triploid karyotypes, they lacked N-myc amplification, and the patients were free of tumor for 12-89 months after diagnosis. All patients in group C except two have near-diploid or hypotetraploid karyotypes, and 21 of 29 patients died within 18 months. One 13-month-old patient (classified in stage 2) and another 7-year-old patient (stage 2) had near-triploid karyotypes and were alive at 74 and 72 months, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Biology of neuroblastomas in Japan found by screening. 145 1

N-myc gene amplification is an unfavorable prognostic factor in neuroblastoma; therefore, its detection might have therapeutical consequences. Because of the reliability of noninvasive diagnostic methods such as X-ray examination and measurement of vanilymandelic acid and the lack of technical unavailability at most institutions, the determination of the N-myc status of neuroblastoma often is not done. In our investigation of 14 neuroblastoma patients, we could demonstrate N-myc gene amplification in the bone marrow of 5 patients with neuroblastoma stage IV disease and in bone marrow infiltration without enrichment of neuroblastoma cells. Otherwise, no information about the tumor content of N-myc gene copies at the time of initial diagnosis could be obtained. At the subsequent resection, the N-myc gene amplification was confirmed by the additional Southern blot analysis and in situ hybridization of tumor tissue. Furthermore, the N-myc status of bone marrow was analyzed during the stages of chemotherapy in three cases.
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PMID:Detection of N-myc gene amplification in bone marrow specimen of stage IV neuroblastoma patients. 145 8

Infectious and transforming activity was obtained from cultures of a large kidney tumour with very high N-myc amplification. The patient belonged to a cluster of neuroblastoma cases diagnosed in Southern Louisiana in 1986-1988. Infection with ultra-filtered supernatants from neuroblastoma cultures caused the appearance of small foci of rounded cells with neural features and the presence of virus was indicated by electron microscopy: the virus was called Micro-Foci inducing virus or MFV. Infected young adult rats did not develop overt disease, but 11/11 of the litters from infected animals developed a very dramatic and highly lethal syndrome which could resemble neuroblastoma symptoms. N-myc amplification disappeared in very early cultures of the tumour, but it was subsequently detected in MFV-infected cell cultures.
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PMID:Isolation and initial characterization of a new virus: Micro-Foci inducing virus or MFV. 146 24

A cell line, established from a neuroblastoma patient, expresses NCAM and L1 cell adhesion molecules. Two chromosomal abnormalities were present in bone marrow (10%) and cell line (82%) metaphases: (i) a homogeneously staining region (HSR) at the distal part of chromosome 14, and (ii) an insertion of unidentified dark G-banding material in 1 p36. The identification in the patient of chr 14-HSR-positive tumour cells, before the in vitro adaptation, suggests a direct HSR formation without preceding double minutes (dms; or a very early in vivo dms----HSR transformation). N-myc was amplified in the HSR. Cells expressed proopiomelanocortin and corticotropin releasing factor mRNAs. Untreated cells were relatively differentiated; nevertheless they dramatically responded to retinoic acid, forming extensive neurites, growth-cones, cell-cell and cell-neurite junctions. Neurofilaments and synaptic figures containing many dense core granules were identified. This differentiation was irreversible. This cell line is therefore useful for the study of differentiation and in particular for the involvement of neurohormones in the differentiation process.
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PMID:An inducible cell line (Natasha), from a neuroblastoma patient with circulating HSR-positive blasts, expressing neurohormones. 150 9

The N-myc amplification of human neuroblastomas was characterized by the amplified DNA cloned from the cell line MC-NB-1 using the phenol emulsion reassociation technique (PERT). A number of PERT clones exhibiting amplification in this cell line were tested for amplification in other neuroblastoma cell lines. In almost all cell lines examined, only a few clones were co-amplified with N-myc and most of the others were exclusively amplified in a subset of the cell lines. The total aggregate size of the Hind III fragment identified by the PERT clones was approximately 350 kb. Most of the PERT clones were mapped to human chromosome (chr) 2p23-2pter, where the N-myc gene is located. Four types of amplicons, the 100, 420, 480 and 520 kb fragments, shown to be Not I fragments, were identified by hexagonal field gel electrophoresis. Three fragments are ordered in a head-to-tail array, and the remaining fragment is either ordered in a tail-to-head array or something else. Despite the extremely unusual construction of the amplified sequences in this cell line as compared with others, there was a low degree of sequence heterogeneity among the amplicons within this cell line. These observations lead to the idea that the complex rearrangements that give rise to the heterogeneous organization of the amplified sequences among the different cell lines precede the amplification of these sequences.
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PMID:Characterization of N-myc amplification in a human neuroblastoma cell line by clones isolated following the phenol emulsion reassociation technique and by hexagonal field gel electrophoresis. 154 99

Neuroblastomas have been characterized genetically by N-myc amplification and by deletions or loss of heterozygosity (LOH) for the short arm of chromosome 1. However, recent studies have suggested deletion or allelic loss involving at least three other chromosome arms, 11q, 14q, and 17p. Therefore, we undertook an analysis of allelic loss for these respective chromosomal arms to determine the frequency and pattern of LOH as well as the correlation of these findings with other biological and clinical variables. A group of 24 pairs of normal and tumor DNAs was chosen that were representative of patients of different ages and stages. A substantial frequency of LOH (greater than or equal to 20%) was found only for 1p and 14q, whereas LOH for the other chromosome arms occurred in less than or equal to 5% of cases. On the basis of these results, we extended the analysis to a total of 59 neuroblastomas, and we found 1p LOH in 15 of the 59 cases (25%) and 14q LOH in 10 of 43 informative cases (23%). N-myc amplification was found in 15 of the 59 cases (25%). This analysis confirmed that 1p LOH and 14q LOH occurred almost exclusively in patients with advanced stages of disease. Furthermore, LOH for 1p and 14q usually occurred independent of each other, and 1p LOH frequently was associated with N-myc amplification, whereas 14q LOH was not. Thus, our results demonstrate that neuroblastomas are complex genetically and that there are at least two distinct loci for putative suppressor genes that are deleted independently in this tumor, both of which are associated with advanced stages of disease.
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PMID:Loss of heterozygosity for chromosomes 1 or 14 defines subsets of advanced neuroblastomas. 155 Nov 8

Tumour samples from 38 patients with neuroblastoma were analysed for the presence of N-myc amplification. N-myc gene copy number in tumour DNA was determined by Southern blotting, and by dilution analysis where appropriate. Available clinical data, obtained at tissue collection and by subsequent questionnaire included patient age at diagnosis, catecholamine, ferritin and neuron-specific enolase levels, treatment and disease status. This study was designed to investigate the use of N-myc amplification data as an additional indicator for determination of prognosis. Patients with amplified N-myc had more rapid disease progression than those without amplification (P less than 0.005). Stratification of Stage III and IV patients using N-myc amplification permitted identification of a subgroup with poorer prognosis. The results demonstrate that determination of N-myc amplification is important in assessment of prognosis and subsequent treatment in patients with neuroblastoma.
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PMID:Association of N-myc amplification with neuroblastoma: the Australian and New Zealand experience. 155 17


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