title: MicroRNA-21 as an indicator of aggressive phenotype in breast cancer.
abstract: OBJECTIVE
  The recently discovered microRNAs (miRNAs) are non-protein-coding, endogenous small RNAs. The aim of this study was to investigate the relationship between microRNA-21 (miR-21) and the clinicopathological features of breast cancer.
  
  
  METHODS
  Formalin-fixed, paraffin-embedded (FFPE) tissue samples were collected from 15 patients who had undergone surgery for primary breast cancer. The miR-21 expression levels in normal and cancer tissues were analyzed using real-time quantitative reverse transcriptase polymerase chain reaction (real-time qRT-PCR). The correlations between the miR-21 expression level and the stage of disease, the tumor size, lymph node involvement, hormone receptor status, human epidermal growth factor receptor 2 (HER2) status, and disease-free survival (DFS) were investigated.
  
  
  RESULTS
  The miR-21 expression levels were significantly higher in patients with stage III disease, patients with more than 3 axillary lymph node metastases and HER2-positive patients than in patients with stage I-II disease, patients with 1-3 axillary lymph node metastases and HER2-negative patients (p = 0.005, p = 0.037, and p = 0.014, respectively). Patients with high miR-21 expression level had a significantly shorter DFS than patients with low miR-21 expression level (median DFS: 18 and 56 months, respectively; p = 0.004).
  
  
  CONCLUSIONS
  These results show that miR-21 is an indicator of an aggressive breast cancer phenotype and that it may be a new therapeutic target in the treatment of breast cancer in the future.
authors.affiliation: Department of Medical Oncology, GATA Haydarpasa Training Hospital, Istanbul, Turkey. alpozgun@yahoo.com
authors.forename: Alpaslan
authors.initials: A
authors.lastname: Ozgün
authors.forename: Bulent
authors.initials: B
authors.lastname: Karagoz
authors.forename: Oguz
authors.initials: O
authors.lastname: Bilgi
authors.forename: Tolga
authors.initials: T
authors.lastname: Tuncel
authors.forename: Huseyin
authors.initials: H
authors.lastname: Baloglu
authors.forename: Emin G
authors.initials: EG
authors.lastname: Kandemir
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000145:classification / Q000175:diagnosis* / Q000378:metabolism*; D005260:Female; D006801:Humans; D035683:MicroRNAs / Q000032:analysis*; D008875:Middle Aged; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor; C524940:MIRN21 microRNA, human; D035683:MicroRNAs