title: Decreased expression of microRNA-31 associates with aggressive tumor progression and poor prognosis in patients with bladder cancer.
abstract: OBJECTIVE
  MicroRNA-31 (miR-31) has different expression patterns in various human cancers. Especially in urothelial carcinoma of the bladder, it has been demonstrated to be decreased expression in the invasive tumors and homozygously deleted. However, its clinical significance in human bladder cancer has not yet been elucidated. Thus, the purpose of this study was to investigate the diagnostic and prognostic values of miR-31 in this disease.
  
  
  METHODS
  Expression levels of miR-31 in 126 pairs of bladder cancer and adjacent normal tissues were detected by real-time quantitative RT-PCR assay. To determine its prognostic value, overall survival (OS) and progression-free survival (PFS) were evaluated using the Kaplan-Meier method, and multivariate analysis was performed using the Cox proportional hazard analysis.
  
  
  RESULTS
  MiR-31 expression in bladder cancer tissues was significantly lower than those in adjacent normal tissues (mean expression level: 2.1 ± 0.9 vs. 3.8 ± 1.2, P < 0.001). When categorized into low vs. high expression, low miR-31 expression was negatively associated with the tumor stage (P = 0.02), the status of recurrence (P = 0.01), progression (P = 0.01), and death (P = 0.006) of patients with bladder cancer. Moreover, low miR-31 expression clearly predicted poorer PFS (P = 0.001) and OS (P < 0.001). In the multivariate analysis, low miR-31 expression was an independent prognostic factor for both PFS (P = 0.01) and OS (P = 0.008).
  
  
  CONCLUSIONS
  These findings show that miR-31 may contribute to the progression of bladder cancer and its downregulation may be independently associated with unfavorable PFS and OS, suggesting that miR-31 might be a promising marker for further risk stratification in the treatment of this cancer.
authors: Department of Urology, The First Affiliated Hospital, Bengbu Medical College, Bengbu, 233030, China.
authors: S
authors: S
authors: Wang
authors: Q
authors: Q
authors: Li
authors: K
authors: K
authors: Wang
authors: Y
authors: Y
authors: Dai
authors: J
authors: J
authors: Yang
authors: S
authors: S
authors: Xue
authors: F
authors: F
authors: Han
authors: Q
authors: Q
authors: Zhang
authors: J
authors: J
authors: Liu
authors: W
authors: W
authors: Wu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics*; D002278:Carcinoma in Situ / Q000235:genetics* / Q000473:pathology; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000473:pathology; D009367:Neoplasm Staging; D011379:Prognosis; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate; D001743:Urinary Bladder / Q000378:metabolism*; D001749:Urinary Bladder Neoplasms / Q000235:genetics* / Q000473:pathology
chemical_list: D014408:Biomarkers, Tumor; C534612:MIRN31 microRNA, human; D035683:MicroRNAs