title: Identification of microRNAs as potential prognostic markers in ependymoma.
abstract: BACKGROUND
  We have examined expression of microRNAs (miRNAs) in ependymomas to identify molecular markers of value for clinical management. miRNAs are non-coding RNAs that can block mRNA translation and affect mRNA stability. Changes in the expression of miRNAs have been correlated with many human cancers.
  
  
  METHODS
  We have utilized TaqMan Low Density Arrays to evaluate the expression of 365 miRNAs in ependymomas and normal brain tissue. We first demonstrated the similarity of expression profiles of paired frozen tissue (FT) and paraffin-embedded specimens (FFPE). We compared the miRNA expression profiles of 34 FFPE ependymoma samples with 8 microdissected normal brain tissue specimens enriched for ependymal cells. miRNA expression profiles were then correlated with tumor location, histology and other clinicopathological features.
  
  
  RESULTS
  We have identified miRNAs that are over-expressed in ependymomas, such as miR-135a and miR-17-5p, and down-regulated, such as miR-383 and miR-485-5p. We have also uncovered associations between expression of specific miRNAs which portend a worse prognosis. For example, we have identified a cluster of miRNAs on human chromosome 14q32 that is associated with time to relapse. We also found that miR-203 is an independent marker for relapse compared to the parameters that are currently used. Additionally, we have identified three miRNAs (let-7d, miR-596 and miR-367) that strongly correlate to overall survival.
  
  
  CONCLUSIONS
  We have identified miRNAs that are differentially expressed in ependymomas compared with normal ependymal tissue. We have also uncovered significant associations of miRNAs with clinical behavior. This is the first report of clinically relevant miRNAs in ependymomas.
authors: Cancer Biology and Epigenomics Program, Children's Memorial Research Center and Department of Pediatrics, Northwestern University's Feinberg School of Medicine, Chicago, Illinois, United States of America. fcosta@childrensmemorial.org
authors: Fabricio F
authors: FF
authors: Costa
authors: Jared M
authors: JM
authors: Bischof
authors: Elio F
authors: EF
authors: Vanin
authors: Rishi R
authors: RR
authors: Lulla
authors: Min
authors: M
authors: Wang
authors: Simone T
authors: ST
authors: Sredni
authors: Veena
authors: V
authors: Rajaram
authors: Maria de Fátima
authors: Mde F
authors: Bonaldo
authors: Deli
authors: D
authors: Wang
authors: Stewart
authors: S
authors: Goldman
authors: Tadanori
authors: T
authors: Tomita
authors: Marcelo B
authors: MB
authors: Soares
mesh_terms: D000293:Adolescent; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D019295:Computational Biology; D004806:Ependymoma / Q000235:genetics* / Q000473:pathology; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007223:Infant; D008297:Male; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D012044:Regression Analysis; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor; C579843:MIRN596 microRNA, human; D035683:MicroRNAs