title: Hypermethylation of the CpG islands in the promoter region flanking GSTP1 gene is a potential plasma DNA biomarker for detecting prostate carcinoma.
abstract: OBJECTIVE
  To investigate the possibility of identifying DNA hypermethylation in the circulation of prostate cancer patients.
  
  
  METHODS
  Plasma DNA samples were extracted from 36 prostate cancer patients and 27 benign prostate hyperplasia (BPH) cases. After extensive methylation-sensitive restriction enzyme digestion, the DNA samples were subjected to the real-time quantitative PCR amplification. Dissociation curve analysis was applied to determine if hypermethylation occurred in the promoter region flanking the GSTP1 gene, a well-documented epigenetic event among prostate cancer cells, in these plasma DNA samples.
  
  
  RESULTS
  11 of 36 prostate cancer patients showed positive peak pattern, indicating methylation changes occurred. Concordant data were obtained from the corresponding paraffin-embedded tissue samples available from the Tumor Bank. Twenty-five of the 27 BPH cases showed negative results, suggesting no methylation changes happened in the CpG islands in these cases.
  
  
  CONCLUSIONS
  We have successfully identified prostate cancer genome hypermethylation in the peripheral circulation in prostate cancer patients with this protocol. This method can effectively distinguish BPH from prostate neoplasm. Although a larger number of samples are necessary to validate the capability of the protocol in practice, using plasma DNA sample is an ideal non-invasive approach for prostate neoplasm detection.
authors.affiliation: Division of Urology, Department of Surgery, Chang Gung Memorial Hospital, Lin-kou, Taiwan.
authors.forename: Cheng-Keng
authors.initials: CK
authors.lastname: Chuang
authors.forename: Da-Chang
authors.initials: DC
authors.lastname: Chu
authors.forename: Ron-Dar
authors.initials: RD
authors.lastname: Tzou
authors.forename: Shu-I
authors.initials: SI
authors.lastname: Liou
authors.forename: Ju-Hsin
authors.initials: JH
authors.lastname: Chia
authors.forename: Chien-Feng
authors.initials: CF
authors.lastname: Sun
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D016022:Case-Control Studies; D018899:CpG Islands; D019175:DNA Methylation; D004273:DNA, Neoplasm / Q000097:blood*; D051549:Glutathione S-Transferase pi / Q000097:blood*; D006801:Humans; D008297:Male; D016612:Paraffin Embedding; D010865:Pilot Projects; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011470:Prostatic Hyperplasia / Q000097:blood / Q000175:diagnosis / Q000235:genetics; D011471:Prostatic Neoplasms / Q000097:blood* / Q000175:diagnosis* / Q000235:genetics; D013624:Taiwan
chemical_list: D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi