title: Methylation of a panel of microRNA genes is a novel biomarker for detection of bladder cancer.
abstract: BACKGROUND
  Dysregulation of microRNAs (miRNAs) has been implicated in bladder cancer (BCa), although the mechanism is not fully understood.
  
  
  OBJECTIVE
  We aimed to explore the involvement of epigenetic alteration of miRNA expression in BCa.
  
  
  METHODS
  Two BCa cell lines (T24 and UM-UC-3) were treated with 5-aza-2'-deoxycytidine (5-aza-dC) and 4-phenylbutyric acid (PBA), after which their miRNA expression profiles were analyzed using a TaqMan array (Life Technologies, Carlsbad, CA, USA). Bisulfite pyrosequencing was used to assess miRNA gene methylation in 5 cancer cell lines, 83 primary tumors, and 120 preoperative and 47 postoperative urine samples.
  
  
  METHODS
  Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic performance of the miRNA gene panel.
  
  
  CONCLUSIONS
  Of 664 miRNAs examined, 146 were upregulated by 5-aza-dC plus PBA. CpG islands were identified in the proximal upstream of 23 miRNA genes, and 12 of those were hypermethylated in cell lines. Among them, miR-137, miR-124-2, miR-124-3, and miR-9-3 were frequently and tumor-specifically methylated in primary cancers (miR-137: 68.7%; miR-124-2: 50.6%; miR-124-3: 65.1%; miR-9-3: 45.8%). Methylation of the same four miRNAs in urine specimens enabled BCa detection with 81% sensitivity and 89% specificity; the area under the ROC curve was 0.916. Ectopic expression of silenced miRNAs in BCa cells suppressed growth and cell invasion.
  
  
  CONCLUSIONS
  Our results indicate that epigenetic silencing of miRNA genes may be involved in the development of BCa and that methylation of miRNA genes could be a useful biomarker for cancer detection.
authors.affiliation: Department of Urology, Sapporo Medical University, Sapporo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Hiromu
authors.initials: H
authors.lastname: Suzuki
authors.forename: Masanori
authors.initials: M
authors.lastname: Nojima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kitamura
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Yamamoto
authors.forename: Reo
authors.initials: R
authors.lastname: Maruyama
authors.forename: Masami
authors.initials: M
authors.lastname: Ashida
authors.forename: Tomo
authors.initials: T
authors.lastname: Hatahira
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kai
authors.forename: Naoya
authors.initials: N
authors.lastname: Masumori
authors.forename: Takashi
authors.initials: T
authors.lastname: Tokino
authors.forename: Kohzoh
authors.initials: K
authors.lastname: Imai
authors.forename: Taiji
authors.initials: T
authors.lastname: Tsukamoto
authors.forename: Minoru
authors.initials: M
authors.lastname: Toyota
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics / Q000652:urine; D002295:Carcinoma, Transitional Cell / Q000175:diagnosis / Q000235:genetics* / Q000652:urine; D045744:Cell Line, Tumor; D018899:CpG Islands; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000235:genetics* / Q000652:urine; D008875:Middle Aged; D012372:ROC Curve; D060888:Real-Time Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000652:urine
chemical_list: D014408:Biomarkers, Tumor; D035683:MicroRNAs