title: Expression of microRNAs associated with Gleason grading system in prostate cancer: miR-182-5p is a useful marker for high grade prostate cancer.
abstract: BACKGROUND
  Expression profiles of some microRNAs (miRNAs) were associated with clinicopathological findings in human prostate cancer (PC), but the relative expression of miRNAs among Gleason patterns (GPs) remains unclear. In this study, we investigated the expression of several known microRNAs in each GP of PC.
  
  
  METHODS
  Formalin-fixed, paraffin embedded (FFPE) tissue samples were obtained from radical prostatectomy (RP) (patient set 1, n = 43, including (GP 3) n = 22, (GP 4) n = 35, and (GP 5) n = 12) and needle biopsy (patient set 2, n = 10, (GP 4) n = 10). Cancer tissues from each GP and adjacent normal counterparts were separately collected using laser-captured microdissection (LCM). Real-time RT-PCR was performed to determine the relative expression of miRNAs, including miR-31-5p, -34c-5p, -96-5p, -182-5p, -183-5p, -205-5p, -221-3p, and -222-3p, which were currently reported to be involved in PC progression.
  
  
  RESULTS
  In radical prostatectomy samples, relative expression of miR-31-5p, miR-34c-5p, and miR-205-5p in any GP was significantly decreased compared to normal counterpart. However, no significant difference was detected among GP 3, GP 4, and GP 5. Meanwhile, in the same GP4, expression of miR-31-5p miR-182-5p, and miR-205-5p in cancer tissues obtained from high grade cancer was significantly higher than those obtained from intermediate grade cancer. Validation study using biopsy samples revealed that the relative expression of miR-182-5p was statistically higher in high grade cancer even in same GP4.
  
  
  CONCLUSIONS
  We confirmed the expression of miR-182-5p depended on the cancer grade even in same GP 4. Expression of miRNA associated with Gleason grading system may contribute to more accurate preoperative cancer risk evaluation.
authors.affiliation: Division of Tumor Pathology, Department of Pathological Sciences, Faculty of Medical Sciences, University of Fukui, Fukui, Japan.
authors.forename: Katsuki
authors.initials: K
authors.lastname: Tsuchiyama
authors.forename: Hideaki
authors.initials: H
authors.lastname: Ito
authors.forename: Minekatsu
authors.initials: M
authors.lastname: Taga
authors.forename: Seiji
authors.initials: S
authors.lastname: Naganuma
authors.forename: Yukinosuke
authors.initials: Y
authors.lastname: Oshinoya
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Nagano
authors.forename: Osamu
authors.initials: O
authors.lastname: Yokoyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Itoh
mesh_terms: D000368:Aged; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000096:biosynthesis* / Q000235:genetics*; D008875:Middle Aged; D060787:Neoplasm Grading; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology*; D012334:RNA, Neoplasm / Q000737:chemistry / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D035683:MicroRNAs; C538984:Mirn182 microRNA, human; D012334:RNA, Neoplasm