title: Serum miRNA-21: elevated levels in patients with metastatic hormone-refractory prostate cancer and potential predictive factor for the efficacy of docetaxel-based chemotherapy.
abstract: BACKGROUND
  miR-21 has been recognized as an "onco-microRNA" with the activity of negatively modulating the expression of tumor-suppressor genes. However, its role in prostate cancer (CaP) has not been well-documented. We designed this study to assess the potential function of serum miR-21 in the progression of CaP.
  
  
  METHODS
  Serum samples of 56 patients, including 20 patients with localized CaP, 20 with androgen-dependent prostate cancer (ADPC), 10 with hormone-refractory prostate cancer (HRPC), and 6 with benign prostatic hyperplasia (BPH), were collected for the measurement of miR-21. The 10 HRPC patients were administered docetaxel-based chemotherapy. Quantification of miR-21 was assayed by specific TaqMan qRT-PCR.
  
  
  RESULTS
  Serum miR-21 level was found to correlate to serum PSA level in patients with ADPC and HRPC, P = 0.012 and 0.049, respectively. There was no significant difference in serum miR-21 level between BPH, localized CaP and ADPC with PSA level <4 ng/ml. Higher levels of miR-21 were detected in patients with HRPC and ADPC with PSA level >4 ng/ml. Six of the 10 HRPC patients reached partial remission with a decreased PSA level of >50% after chemotherapy. Serum miR-21 levels were higher in patients who were resistant to docetaxel-based chemotherapy when compared to those sensitive to chemotherapy, P = 0.032.
  
  
  CONCLUSIONS
  Serum miR-21 levels are elevated in HRPC patients, especially in those resistant to docetaxel-based chemotherapy. It may be applicable as a marker to indicate the transformation to hormone refractory disease, and a potential predictor for the efficacy of docetaxel-based chemotherapy.
authors.affiliation: Department of Urology, Fudan University Shanghai Cancer Center, Shanghai, PR China.
authors.forename: Hai-Liang
authors.initials: HL
authors.lastname: Zhang
authors.forename: Li-Feng
authors.initials: LF
authors.lastname: Yang
authors.forename: Yao
authors.initials: Y
authors.lastname: Zhu
authors.forename: Xu-Dong
authors.initials: XD
authors.lastname: Yao
authors.forename: Shi-Lin
authors.initials: SL
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Dai
authors.forename: Yi-Ping
authors.initials: YP
authors.lastname: Zhu
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Shen
authors.forename: Guo-Hai
authors.initials: GH
authors.lastname: Shi
authors.forename: Ding-Wei
authors.initials: DW
authors.lastname: Ye
mesh_terms: D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D000077143:Docetaxel; D006801:Humans; D008297:Male; D035683:MicroRNAs / Q000097:blood*; D008875:Middle Aged; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy / Q000235:genetics; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology; D043823:Taxoids / Q000627:therapeutic use*
chemical_list: D000970:Antineoplastic Agents; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D043823:Taxoids; D000077143:Docetaxel; D017430:Prostate-Specific Antigen