Hypermethylation of the CpG islands in the promoter region flanking GSTP1 gene is a potential plasma DNA biomarker for detecting prostate carcinoma.
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.
Chuang
Cheng-Keng
CK
Division of Urology, Department of Surgery, Chang Gung Memorial Hospital, Lin-kou, Taiwan.
Chu
Da-Chang
DC
Tzou
Ron-Dar
RD
Liou
Shu-I
SI
Chia
Ju-Hsin
JH
Sun
Chien-Feng
CF
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
D014408:Biomarkers, Tumor; D004273:DNA, Neoplasm; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi