Detection of alpha-methylacyl-coenzyme-A racemase transcripts in blood and urine samples of prostate cancer patients.
BACKGROUND
Alpha-methylacyl-coenzyme-A racemase (AMACR) has been shown to be a highly specific marker for prostate cancer cells, even in the earliest stages of malignant progression. It is expressed at much higher levels than prostate-specific antigen (PSA) in malignant tissues, and is not expressed at appreciable levels in normal prostatic epithelium. In this study, we demonstrate the quantitative detection of AMACR transcripts in peripheral blood of prostate cancer patients using real-time RT-PCR. In addition, we have undertaken a pilot study to demonstrate the potential application of this technique for the detection of prostate tumor cells in urine samples from patients with prostate cancer.


METHODS
A real-time RT-PCR assay was developed for detection of the expression of AMACR in prostate cancer patients. Blood samples from 163 patients were tested at various stages of disease progression, with or without therapy. Blood specimens from patients with benign prostate disorders and other types of cancer were also evaluated.


RESULTS
In 28 of 58 samples from patients with known metastatic disease who were undergoing treatment, an AMACR expression signal above the cut-off value was detected, consistent with the presence of circulating tumor cells. In 39 of 88 patients with presumptive organ-confined disease, there was evidence of low levels of circulating tumor cells. Comparison of AMACR RT-PCR with known serum PSA values indicated that a combination of these parameters significantly increased the sensitivity for detection of progressive disease. In a pilot study analyzing urine samples from seven prostate cancer patients, elevated AMACR expression levels were detected in the urine sediments of four of six stage-T1 prostate cancer patients and in the one patient with stage-T2 prostate cancer.


CONCLUSIONS
The data presented in this study indicates that AMACR real-time RT-PCR may aid in the detection and staging of prostate cancer.
Zehentner
Barbara K
BK
HematoLogics Inc., Seattle, Washington 98109, USA. barbara@hematologics.com
Secrist
Heather
H
Zhang
XinQun
X
Hayes
Dawn C
DC
Ostenson
Richard
R
Goodman
Gary
G
Xu
Jiangchun
J
Kiviat
Mark
M
Kiviat
Nancy
N
Persing
David H
DH
Houghton
Raymond L
RL
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D017430:Prostate-Specific Antigen / Q000097:blood* / Q000652:urine*; D011471:Prostatic Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology* / Q000652:urine; D012334:RNA, Neoplasm / Q000032:analysis; D019998:Racemases and Epimerases / Q000097:blood / Q000235:genetics* / Q000652:urine; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012680:Sensitivity and Specificity
D014408:Biomarkers, Tumor; D012334:RNA, Neoplasm; D017430:Prostate-Specific Antigen; D019998:Racemases and Epimerases; C108352:alpha-methylacyl-CoA racemase