Immunocytochemical analysis of prostate stem cell antigen as adjunct marker for detection of urothelial transitional cell carcinoma in voided urine specimens.
OBJECTIVE
Prostate stem cell antigen (PSCA), a homologue of the Ly-6/Thy-1 family of cell surface antigens, has been shown to be increased in a majority of human transitional cell carcinomas. We tested the possibility of using PSCA as an adjunct marker for urine cytology.


METHODS
Immunocytochemical analysis was performed on 44 archived voided urine samples obtained from 3 groups of patients based on initial voided urine cytological results and subsequent followup biopsy findings. Group 1 (14 of 44 patients) had positive findings on cytology and histology, group 2 (16 of 44) had negative cytology but positive histology, and group 3 (14 of 44) had negative findings on cytology and histology. Cytological slides prepared from 10 fresh voided urine samples were also analyzed. Papanicoloau stained archived urine slides were de-stained and re-stained immunocytochemically with a monoclonal antibody against PSCA. Immunofluorescence followed by laser scanning cytometer analysis was also performed on archived slides from 2 representative cases.


RESULTS
Sensitivity and specificity were 46.7% and 100% for cytology alone, respectively, and 80% and 85.7% for PSCA alone, respectively. PSCA immunostaining was positive in 92.8% group 1, 68.8% group 2 and only 14.3% group 3 samples. The difference in positive PSCA findings in groups 2 and 3 were statistically significant at p <0.01 by chi-square test. Whereas some superficial umbrella cells showed slight staining by immunocytochemistry, it was feasible to distinguish the expression levels between tumor and normal superficial umbrella cells quantitatively using immunofluorescence coupled with laser scan cytometry analysis.


CONCLUSIONS
Immunocytochemical analysis of PSCA on archived voided urine samples may provide a simple and quantitative adjunct marker for cytological diagnosis of urothelial carcinoma.
Cheng
Lirong
L
Department of Pathology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, USA.
Reiter
Robert E
RE
Jin
Yusheng
Y
Sharon
Hirschowitz
H
Wieder
Jeffrey
J
Lane
Timothy F
TF
Rao
Jianyu
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000652:urine*; D014408:Biomarkers, Tumor / Q000652:urine*; D002295:Carcinoma, Transitional Cell / Q000175:diagnosis*; D003581:Cytodiagnosis; D005260:Female; D005455:Fluorescent Antibody Technique; D058851:GPI-Linked Proteins; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008562:Membrane Glycoproteins / Q000652:urine*; D018613:Microscopy, Confocal; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000652:urine*; D012680:Sensitivity and Specificity; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis*; D014556:Urine / Q000166:cytology
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; C110843:PSCA protein, human