title: Identification of genes that are regulated transcriptionally by Myc in childhood tumors.
abstract: BACKGROUND
  Amplification of the N-myc oncogene is associated with adverse outcomes in the common childhood tumor, neuroblastoma. Because the transforming properties of Myc are related to its ability to modulate gene expression, the authors used cDNA microarrays to identify potential Myc target genes.
  
  
  METHODS
  Expression levels of 4608 genes were analyzed in a series of neuroblastoma cell lines. Identical analyses were performed in a panel of medulloblastoma cell lines to identify c-Myc targets and to determine the extent to which N-Myc targets and c-Myc targets were shared. Comparisons were made between cell lines with high levels versus low levels of Myc protein expression.
  
  
  RESULTS
  Array analyses yielded 121 genes with increased expression levels (>or= 1.65-fold) and 9 genes with decreased expression levels in N-Myc-expressing versus nonexpressing cell lines. Many of these were newly identified targets of biologic interest. Fifty percent of the N-Myc targets (60 of 121) were mutual c-Myc targets. A significant correlation between the level of N-myc and selected target gene expression was demonstrated independently in 27 neuroblastoma tumor samples and in an N-myc-inducible cell line system.
  
  
  CONCLUSIONS
  A number of diverse pathways are modulated by N-Myc in neuroblastoma. Although, overall, there was significant correlation between myc and target transcript expression among cohorts of tumors, great variability in levels of target expression was seen among individual tumor samples, and this biologic heterogeneity in the levels of target gene expression may offer insight into differences in the clinical behavior of neuroblastoma and may prove to be of prognostic significance in the future.
authors.affiliation: Mount Sinai School of Medicine, New York, New York, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Raetz
authors.forename: Marianne K H
authors.initials: MK
authors.lastname: Kim
authors.forename: Philip
authors.initials: P
authors.lastname: Moos
authors.forename: Marlee
authors.initials: M
authors.lastname: Carlson
authors.forename: Carol
authors.initials: C
authors.lastname: Bruggers
authors.forename: David K
authors.initials: DK
authors.lastname: Hooper
authors.forename: Laura
authors.initials: L
authors.lastname: Foot
authors.forename: Tong
authors.initials: T
authors.lastname: Liu
authors.forename: Robert
authors.initials: R
authors.lastname: Seeger
authors.forename: William L
authors.initials: WL
authors.lastname: Carroll
mesh_terms: D015153:Blotting, Western; D002528:Cerebellar Neoplasms / Q000235:genetics*; D002648:Child; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D016259:Genes, myc / Q000502:physiology*; D006801:Humans; D008527:Medulloblastoma / Q000235:genetics*; D009447:Neuroblastoma / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D014407:Tumor Cells, Cultured