title: The clinico-pathologic role of microRNAs miR-9 and miR-151-5p in breast cancer metastasis.
abstract: BACKGROUND
  MicroRNAs (miRNAs) may function as suppressors or promoters of tumor metastasis according to their messenger RNA targets. Previous studies have suggested that miR-9 and miR-151-5p are associated with metastasis in breast cancer and hepatocellular carcinoma, respectively. We aimed to further establish the potential roles of miR-9 and miR-151-5p in tumor invasion and metastasis and investigate their use as biomarkers.
  
  
  METHODS
  We used quantitative real-time PCR (qRT-PCR) to measure differences in miR-9 and miR-151-5p expression between primary breast tumors and their lymph-node metastases in 194 paired tumor samples from 97 patients. We also correlated expression levels with histologic data to investigate their utility as biomarkers.
  
  
  RESULTS
  There were no significant differences in miR-9 expression between the primary tumors and lymph nodes; however, miR-151-5p expression was significantly lower in the lymph-node metastases than in their corresponding tumors (p < 0.05). miR-9 levels were elevated in primary breast tumors from patients diagnosed with higher-grade tumors (p < 0.05); however, no differences were observed in miR-151-5p levels between different grades of tumor. Interestingly, miR-9 levels were elevated in invasive lobular carcinomas (ILC) compared with invasive ductal carcinomas (IDC; p < 0.01).
  
  
  CONCLUSIONS
  In aggregate, these data suggest that miR-151-5p upregulation may suppress metastasis in primary breast tumors. Both miRNAs may serve as useful biomarkers in future clinical trials in breast cancer.
authors.affiliation: Division of Oncology, Department of Surgery & Cancer, Imperial College, London, UK. j.krell@imperial.ac.uk
authors.forename: Jonathan
authors.initials: J
authors.lastname: Krell
authors.forename: Adam E
authors.initials: AE
authors.lastname: Frampton
authors.forename: Jimmy
authors.initials: J
authors.lastname: Jacob
authors.forename: Loredana
authors.initials: L
authors.lastname: Pellegrino
authors.forename: Laura
authors.initials: L
authors.lastname: Roca-Alonso
authors.forename: Daniel
authors.initials: D
authors.lastname: Zeloof
authors.forename: Costi
authors.initials: C
authors.lastname: Alifrangis
authors.forename: Jacqueline S
authors.initials: JS
authors.lastname: Lewis
authors.forename: Long R
authors.initials: LR
authors.lastname: Jiao
authors.forename: Justin
authors.initials: J
authors.lastname: Stebbing
authors.forename: Leandro
authors.initials: L
authors.lastname: Castellano
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008207:Lymphatic Metastasis / Q000235:genetics*; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D014408:Biomarkers, Tumor; C548886:MIRN151a microRNA, human; C541874:MIRN92 microRNA, human; D035683:MicroRNAs