DD3(PCA3)-based molecular urine analysis for the diagnosis of prostate cancer.
BACKGROUND
DD3(PCA3) is the most prostate cancer-specific gene described to date. To assess the clinical utility of DD3(PCA3) a time-resolved fluorescence-based, quantitative RT-PCR analysis for DD3(PCA3) was developed.


METHODS
The diagnostic potential of DD3(PCA3) was determined by quantitative measurement of DD3(PCA3) transcripts in non-malignant and malignant prostate specimens. Moreover, DD3(PCA3) transcripts were determined quantitatively in urine sediments obtained after prostatic massage. A cohort of 108 men, admitted for prostate biopsies based on a PSA of >3ng/ml, was studied.


RESULTS
Prostate tumors showed a 66-fold up-regulation of DD3(PCA3) (median 158.4.10(5) copies/microg tissue RNA) when compared to benign prostate tissue (median 2.4.10(5) copies/microg tissue RNA). This up-regulation was found in more than 95% of prostate cancer specimens studied. These data revealed that specimens with less than 10% of cancer cells could be accurately discriminated from non-cancer tissues. Hence, detection of a small fraction of prostate cancer cells in a background of normal cells seemed feasible. Therefore, this DD3(PCA3)-based RT-PCR assay was used for the identification of prostate cancer in urine sediments obtained after prostatic massage. From 108 men with a serum PSA value >3ng/ml, 24 men were shown to have prostate cancer upon biopsy. Of these 24 men, 16 were shown to be positive for DD3(PCA3), indicating a sensitivity of the assay of 67%. Furthermore, a negative predictive value of 90% was calculated.


CONCLUSIONS
The quantitative RT-PCR assay for DD3(PCA3) described, bears great promise as a tool for molecular urine analysis. It has great potential in reducing the number of unnecessary biopsies. A multi-center study using this DD3(PCA3) assay can provide the basis for the utility of molecular diagnostics in clinical urological practice.
Hessels
Daphne
D
Department of Experimental Urology, Nijmegen Center for Molecular Life Sciences, P.O Box 9101, 6500 HB Nijmegen, The Netherlands.
Klein Gunnewiek
Jacqueline M T
JM
van Oort
Inge
I
Karthaus
Herbert F M
HF
van Leenders
Geert J L
GJ
van Balken
Bianca
B
Kiemeney
Lambertus A
LA
Witjes
J Alfred
JA
Schalken
Jack A
JA
D000368:Aged; D001483:Base Sequence; D001707:Biopsy, Needle; D016022:Case-Control Studies; D015331:Cohort Studies; D015972:Gene Expression Regulation, Neoplastic; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011237:Predictive Value of Tests; D011379:Prognosis; D017430:Prostate-Specific Antigen / Q000235:genetics* / Q000652:urine; D011468:Prostatectomy / Q000379:methods; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D012334:RNA, Neoplasm / Q000032:analysis; D012372:ROC Curve; D012016:Reference Values; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity
D012334:RNA, Neoplasm; D017430:Prostate-Specific Antigen