title: microRNA profiling identifies cancer-specific and prognostic signatures in pediatric malignancies.
abstract: OBJECTIVE
  microRNAs have been shown to be involved in different human cancers. We therefore have performed expression profiles on a panel of pediatric tumors to identify cancer-specific microRNAs. We also investigated if microRNAs are coregulated with their host gene.
  
  
  METHODS
  We performed parallel microRNAs and mRNA expression profiling on 57 tumor xenografts and cell lines representing 10 different pediatric solid tumors using microarrays. For those microRNAs that map to their host mRNA, we calculated correlations between them.
  
  
  RESULTS
  We found that the majority of cancer types clustered together based on their global microRNA expression profiles by unsupervised hierarchical clustering. Fourteen microRNAs were significantly differentially expressed between rhabdomyosarcoma and neuroblastoma, and 8 of them were validated in independent patient tumor samples. Exploration of the expression of microRNAs in relationship with their host genes showed that the expression for 43 of 68 (63%) microRNAs located inside known coding genes was significantly correlated with that of their host genes. Among these 43 microRNAs, 5 of 7 microRNAs in the OncomiR-1 cluster correlated significantly with their host gene MIRHG1 (P < 0.01). In addition, high expression of MIRHG1 was significantly associated with high stage and MYCN amplification in neuroblastoma tumors, and the expression level of MIRHG1 could predict the outcome of neuroblastoma patients independently from the current neuroblastoma risk-stratification in two independent patient cohorts.
  
  
  CONCLUSIONS
  Pediatric cancers express cancer-specific microRNAs. The high expression of the OncomiR-1 host gene MIRHG1 correlates with poor outcome for patients with neuroblastoma, indicating important oncogenic functions of this microRNA cluster in neuroblastoma biology.
authors.affiliation: Oncogenomics Section, Pediatric Oncology Branch, Advanced Technology Center, National Cancer Institute, Gaithersburg, Maryland 20877, USA. weij@mail.nih.gov
authors.forename: Jun S
authors.initials: JS
authors.lastname: Wei
authors.forename: Peter
authors.initials: P
authors.lastname: Johansson
authors.forename: Qing-Rong
authors.initials: QR
authors.lastname: Chen
authors.forename: Young K
authors.initials: YK
authors.lastname: Song
authors.forename: Steffen
authors.initials: S
authors.lastname: Durinck
authors.forename: Xinyu
authors.initials: X
authors.lastname: Wen
authors.forename: Adam T C
authors.initials: AT
authors.lastname: Cheuk
authors.forename: Malcolm A
authors.initials: MA
authors.lastname: Smith
authors.forename: Peter
authors.initials: P
authors.lastname: Houghton
authors.forename: Christopher
authors.initials: C
authors.lastname: Morton
authors.forename: Javed
authors.initials: J
authors.lastname: Khan
mesh_terms: D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D045744:Cell Line, Tumor; D002648:Child; D020869:Gene Expression Profiling; D006801:Humans; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics; D009369:Neoplasms / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D011379:Prognosis
chemical_list: D014408:Biomarkers, Tumor; D035683:MicroRNAs
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