Development of a multiplexed urine assay for prostate cancer diagnosis.
BACKGROUND
Several studies have demonstrated the value of DNA methylation in urine-based assays for prostate cancer diagnosis. However, a multicenter validation with a clinical prototype has not been published.


METHODS
We developed a multiplexed, quantitative methylation-specific polymerase chain reaction (MSP) assay consisting of 3 methylation markers, GSTP1, RARB, and APC, and an endogenous control, ACTB, in a closed-tube, homogeneous assay format. We tested this format with urine samples collected after digital rectal examination from 234 patients with prostate-specific antigen (PSA) concentrations > or =2.5 microg/L in 2 independent patient cohorts from 9 clinical sites.


RESULTS
In the first cohort of 121 patients, we demonstrated 55% sensitivity and 80% specificity, with area under the curve (AUC) 0.69. In the second independent cohort of 113 patients, we found a comparable sensitivity of 53% and specificity of 76% (AUC 0.65). In the first cohort, as well as in a combined cohort, the MSP assay in conjunction with total PSA, digital rectal examination status, and age improved the AUC without MSP, although the difference was not statistically significant. Importantly, the GSTP1 cycle threshold value demonstrated a good correlation (R = 0.84) with the number of cores found to contain prostate cancer or premalignant lesions on biopsy. Moreover, samples that exhibited methylation for either GSTP1 or RARB typically contained higher tumor volumes at prostatectomy than those samples that did not exhibit methylation.


CONCLUSIONS
These data confirm and extend previously reported studies and demonstrate the performance of a clinical prototype assay that should aid urologists in identifying men who should undergo biopsy.
Vener
Tatiana
T
Veridex LLC, Johnson & Johnson Company, Warren, NJ 07059, USA.
Derecho
Carlo
C
Baden
Jonathan
J
Wang
Haiying
H
Rajpurohit
Yashoda
Y
Skelton
Joanne
J
Mehrotra
Jyoti
J
Varde
Shobha
S
Chowdary
Dondapati
D
Stallings
Walt
W
Leibovich
Bradley
B
Robin
Howard
H
Pelzer
Alexandre
A
Schäfer
Georg
G
Auprich
Marco
M
Mannweiler
Sebastian
S
Amersdorfer
Peter
P
Mazumder
Abhijit
A
D025601:Adenomatous Polyposis Coli Protein / Q000235:genetics; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D019175:DNA Methylation; D051549:Glutathione S-Transferase pi / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000652:urine; D018168:Receptors, Retinoic Acid / Q000235:genetics; D012680:Sensitivity and Specificity
D025601:Adenomatous Polyposis Coli Protein; D018168:Receptors, Retinoic Acid; C082925:retinoic acid receptor beta; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi