The clinical utility of the prostate specific membrane antigen reverse-transcription/polymerase chain reaction to detect circulating prostate cells: an analysis in healthy men and women.
OBJECTIVE
To evaluate the overall specificity of nested reverse transcriptase-polymerase chain reaction (RT-PCR) to detect prostate-specific membrane antigen (PSM) mRNA in peripheral blood samples of healthy donors.


METHODS
Peripheral blood samples were taken from 60 healthy blood-donors (30 men and 30 women aged < 50 years) and analysed for PSM-mRNA using nested RT-PCR (in 'hot-start' conditions and confirmed using nested EcoRI restriction enzyme). Intron-spanning primer pairs specific for human PSM were deduced from the GenBank sequence (M99487) using gene software. The outer primer pair for PSM was: fwd: 1368 5'-TCACCGGGACTCATGGGTGT-3'; reverse: 1860 5'-GCCTGAAGCAATTCCAAGTCGG-3'. Inner primer pair for PSM was: fwd: 1480 5'-AAGGAAGGGTGGAGACCTAG-3'; reverse: 5-ACTGAACTCTGGGGAAGGAC-3'. The integrity of cDNAs was checked using primer pairs specific for the housekeeping gene beta-actin. The specificity and false-positive rate were calculated assuming that the underlying prostate cancer incidence was nil.


RESULTS
The first PCR was negative for all samples (100% specificity; 0% false-positive rate). The nested PCR detected 23 positive samples (23/60, 38%) with an overall specificity of 62% (false positive rate, 38%).


CONCLUSIONS
Nested RT-PCR of PSM-mRNA in peripheral blood is highly unspecific. Its clinical utility in the management of prostate cancer must be low. Further development is needed of quantitative RT-PCR, primers that identify prostatic PSM or another prostate-specific marker gene to differentiate PSM mRNA from circulating prostate cells and from non-prostatic tissues.
Llanes
L
L
Department of Urology, Hospital Universitario de Getafe, Madrid, Spain.
Ferruelo
A
A
Páez
A
A
Gómez
J M
JM
Moreno
A
A
Berenguer
A
A
D000328:Adult; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D011467:Prostate / Q000166:cytology*; D017430:Prostate-Specific Antigen / Q000097:blood*; D012333:RNA, Messenger / Q000097:blood; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000592:standards*; D012680:Sensitivity and Specificity
D012333:RNA, Messenger; D017430:Prostate-Specific Antigen