Reverse transcriptase-polymerase chain reaction and immunohistochemical studies for detection of prostate stem cell antigen expression in prostate cancer: potential value in molecular staging of prostate cancer.
OBJECTIVE
To determine whether detection of prostate stem cell antigen (PSCA) expression has potential for molecular staging in prostate cancer (PCa), we examined the relationship between established prognostic factors, biochemical recurrence (BCR) and PSCA expression.


METHODS
This study was comprised of 66 patients who underwent radical prostatectomy for the treatment of PCa. We employed reverse transcriptase-polymerase chain reaction (RT-PCR) to detect PSCA mRNA-bearing cells in peripheral blood, and used immunohistochemical (IHC) techniques to identify PSCA protein expression in microarrayed tissue.


RESULTS
PSCA-mRNA was detected in the peripheral blood of nine (13.6%) patients by RT-PCR. Whereas 3.2% of patients with low-grade disease were PSCA positive, 22.9% of patients with high-grade disease were PSCA positive (P = 0.030). There was also a significant relationship of RT-PCR PSCA positivity to whether or not the tumor was confined to the prostate. Whereas only 6.8% of patients with prostate-confined disease were RT-PCR PSCA positive, 27.3% of extraprostatic diseases were RT-PCR PSCA positive (P = 0.022). IHC studies of tumor tissue microarrays demonstrated that PSCA expression intensity was related to both extraprostatic extension (P = 0.014) and positive surgical margin (P = 0.053). Whereas 23.8% of prostate-confined diseases were high intensity, 54.5% of extraprostatic diseases were high intensity. BCR developed in seven patients (10.6%) during the follow-up period (median, 16.2 months; range, 9-25 months). Prognostic factors increasing the risk of BCR included: seminal vesicle invasion (P = 0.004), extraprostatic disease (P = 0.019), lymphovascular emboli (P = 0.036) and RT-PCR PSCA positivity (P = 0.004) in univariate analysis.


CONCLUSIONS
We were able to detect PSCA mRNA-bearing cells in peripheral blood by RT-PCR, and also identify PSCA protein expression in tumors by IHC analysis of tissue microarrays. RT-PCR PSCA positivity in peripheral blood may be a potential modality for molecular staging of PCa.
Joung
Jae Young
JY
Urologic Oncology Clinic, Institute and Hospital, National Cancer Center, 809 Madu-Dong, Ilnsan-Gu, Goyang, Gyonggi 410-769 Korea.
Yang
Seung Ok
SO
Jeong
In Gab
IG
Han
Kyung Suk
KS
Seo
Ho Kyung
HK
Chung
Jinsoo
J
Park
Weon Seo
WS
Lee
Kang Hyun
KH
D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm; D058851:GPI-Linked Proteins; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis* / Q000235:genetics; D046228:Microarray Analysis; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis* / Q000235:genetics; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis; D009367:Neoplasm Staging; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood / Q000737:chemistry* / Q000473:pathology / Q000601:surgery; D012333:RNA, Messenger / Q000097:blood; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000951:Antigens, Neoplasm; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; C110843:PSCA protein, human; D012333:RNA, Messenger