title: Prognostic and biological significance of microRNA-221 in breast cancer.
abstract: BACKGROUND
  Breast cancer (BC) is the most notorious cancer between females with high rates of morbidity and mortality. The aim of this study was to determine the differential expression of breast tissues microRNA-221 (miR-221) and assess its prognostic and biological significance in breast cancer (BC).
  
  
  METHODS
  A quantitative reverse transcription PCR (qPCR) assay was performed to detect the expression of breast tissue miR-221 in different subtypes of BC (n=76) and controls (n=36) and its correlations with clinicopathological factors of patients. Univariate and multivariate analyses using the Cox proportional hazards model were performed to analyze the prognostic significance of miR-221 expression.
  
  
  RESULTS
  Our data indicated that the relative level of miR-221 expression in BC tissues was significantly higher than that in noncancerous breast tissues (p<0.01). Of 76 BC patients, 62 (81.6%) were positive cases. By statistical analyses, high miR-221 expression was observed to be closely correlated with advanced clinical stage (p<0.01). Moreover, patients with high miR-221 expression had worse 5-year relapse free survival (p=0.0124). Univariate and multivariate analyses indicated that high miR-221 expression was an independent poor prognostic factor for BC patients.
  
  
  CONCLUSIONS
  miR-221 is a potential biomarker for predicting the survival of BC patients and may be a molecular therapeutic target for BC.
authors.affiliation: Oncology Diagnostic Unit, Medical Biochemistry and Molecular Biology Department, Faculty of Medicine, Ain Shams University, P.O. Box 11381, Abbassia, Cairo, Egypt.
authors.forename: Sanaa
authors.initials: S
authors.lastname: Eissa
authors.affiliation: Oncology Diagnostic Unit, Medical Biochemistry and Molecular Biology Department, Faculty of Medicine, Ain Shams University, P.O. Box 11381, Abbassia, Cairo, Egypt.
authors.forename: Marwa
authors.initials: M
authors.lastname: Matboli
authors.affiliation: Biochemistry Department, Faculty of Pharmacy, Misr University for Science and Technology (MUST), 6th of October City, Egypt.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Sharawy
authors.affiliation: Biochemistry and Molecular Biology Department, Faculty of Pharmacy, Helwan University, Egypt. Electronic address: felsharkawi@gmail.com.
authors.forename: Fathia
authors.initials: F
authors.lastname: El-Sharkawi
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics*; D016022:Case-Control Studies; D018572:Disease-Free Survival; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D006801:Humans; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000235:genetics; D011379:Prognosis
chemical_list: D014408:Biomarkers, Tumor; D035683:MicroRNAs; C525709:MIR221, human
keywords: Breast cancer; Databases; Prognosis; Survival; miR-221