title: Differential expression of miR-139, miR-486 and miR-21 in breast cancer patients sub-classified according to lymph node status.
abstract: OBJECTIVE
  Therapeutic decisions in breast cancer are increasingly guided by prognostic and predictive biomarkers. Non-protein-coding microRNAs (miRNAs) have recently been found to be deregulated in breast cancers and, in addition, to be correlated with several clinico-pathological features. One of the most consistently up-regulated miRNAs is miR-21. Here, we specifically searched for differentially expressed miRNAs in high-risk breast cancer patients as compared to low-risk breast cancer patients. In the same patients, we also compared miR-21 expression with the expression of its presumed target PTEN.
  
  
  METHODS
  Both microarray and RT-qPCR techniques were used to assess miRNA expression levels in lymph node-positive and -negative human invasive ductal carcinoma tissues. Simultaneously, PTEN protein expression levels were assessed using immunohistochemistry.
  
  
  RESULTS
  miR-486-5p and miR-139-5p were found to be down-regulated in patients with lymph node metastases, whereas miR-21 was found to be up-regulated in patients with a positive lymph node status. miR-21 expression levels were found to significantly correlate with tumour size (r = 0.403, p = 0.009; Spearman's rank), whereas no relation was found between miR-21 and PTEN expression levels (Kruskal-Wallis test).
  
  
  CONCLUSIONS
  Down-regulation of miR-486-5p and miR-139-5p, in conjunction with up-regulation of miR-21, may represent a useful signature for the identification of high-risk breast cancer patients.
authors.affiliation: Department of Oncology 54O5, Herlev Hospital, University of Copenhagen, Herlev Ringvej 75, 2730, Herlev, Denmark, lene.rask.01@regionh.dk.
authors.forename: Lene
authors.initials: L
authors.lastname: Rask
authors.forename: Eva
authors.initials: E
authors.lastname: Balslev
authors.forename: Rolf
authors.initials: R
authors.lastname: Søkilde
authors.forename: Estrid
authors.initials: E
authors.lastname: Høgdall
authors.forename: Henrik
authors.initials: H
authors.lastname: Flyger
authors.forename: Jens
authors.initials: J
authors.lastname: Eriksen
authors.forename: Thomas
authors.initials: T
authors.lastname: Litman
mesh_terms: D000368:Aged; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000145:classification / Q000175:diagnosis / Q000235:genetics*; D015536:Down-Regulation; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D015854:Up-Regulation
chemical_list: C555098:MIRN139 microRNA, human; C524940:MIRN21 microRNA, human; C560945:MIRN486 microRNA, human; D035683:MicroRNAs; D051059:PTEN Phosphohydrolase