title: Downregulation and prognostic performance of microRNA 224 expression in prostate cancer.
abstract: BACKGROUND
  The extensive use of prostate-specific antigen as a general prostate cancer biomarker has introduced the hazards of overdiagnosis and overtreatment. Recent studies have revealed the immense biomarker capacity of microRNAs (miRNAs) in prostate cancer. The aim of this study was to analyze the expression pattern of miR-224, a cancer-related miRNA, in prostate tumors and investigate its clinical utility.
  
  
  METHODS
  Total RNA was isolated from 139 prostate tissue samples. After the polyadenylation of total RNA by poly(A) polymerase, cDNA was synthesized with a suitable poly(T) adapter. miR-224 expression was assessed by quantitative real-time PCR and analyzed with the comparative quantification cycle method, C(q)(2(-ΔΔCq)). We performed comprehensive biostatistical analyses to explore the clinical value of miR-224 in prostate cancer.
  
  
  RESULTS
  miR-224 expression was significantly downregulated in malignant samples compared with benign samples (P < 0.001). Higher miR-224 expression levels were found in prostate tumors that were less aggressive (P = 0.017) and in an earlier disease stage (P = 0.018). Patients with prostate cancer who were positive for miR-224 had significantly enhanced progression-free survival intervals compared with miR-224-negative patients (P = 0.021). Univariate bootstrap Cox regression confirmed that miR-224 was associated with favorable prognosis (hazard ratio 0.314, P = 0.013); nonetheless, multivariate analysis, adjusted for conventional markers, did not identify miR-224 as an independent prognostic indicator.
  
  
  CONCLUSIONS
  miR-224 is aberrantly expressed in prostate cancer. Its assessment by cost-effective quantitative molecular methodologies could provide a useful biomarker for prostate cancer.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Athens, Athens, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Mavridis
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Stravodimos
authors.forename: Andreas
authors.initials: A
authors.lastname: Scorilas
mesh_terms: D001483:Base Sequence; D014408:Biomarkers, Tumor; D017931:DNA Primers; D015536:Down-Regulation; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D014408:Biomarkers, Tumor; D017931:DNA Primers; C546140:MIRN224 microRNA, human; D035683:MicroRNAs; D017430:Prostate-Specific Antigen