Fluorescent methylation-specific polymerase chain reaction for DNA-based detection of prostate cancer in bodily fluids

Promoter hypermethylation of the glutathione S-transferase PI gene (GSTP1) is the most frequent DNA alteration in prostatic carcinoma. Because this ep igenetic DNA alteration can be reliably detected by methylation-specific PC R (MSP), we applied this new technique for molecular detection of prostate cancer in various human bodily fluids. We investigated GSTP1 promoter hyper methylation in DNA isolated from plasma, serum, ejaculate, and urine after prostate massage and from prostate carcinoma tissues from 33 patients with prostate cancer and 26 control patients with benign prostatic hyperplasia ( BPH). Fluorescently labeled MSP products were analyzed on an automated gene sequencer. Whereas GSTP1 promoter hypermethylation was not detectable by M SP in prostate tissue and bodily fluids from patients with BPH, we found it in 94% of tumors (16 of 17), 72% of plasma or serum samples (23 of 32), 50 % of ejaculate (4 of 8) and 36% of urine (4 of 11) from patients with prost ate cancer. Additionally, MSP identified circulating tumor cells in 30% (10 of 33) of prostate cancer patients. Analysis of GSTP1 promoter hypermethyl ation by MSP thus provides a specific tool for molecular diagnosis of prost ate cancer in bodily fluids.