Polyclonal anti-PSA is more sensitive but less specific than monoclonal anti-PSA: Implications for diagnostic prostatic pathology.
Prostate-specific antigen (PSA) production by nonprostatic tissues has been reported, casting doubts on its specificity. The immunohistochemical relative specificity and sensitivity of PSA expression using monoclonal and polyclonal anti-PSA was analyzed on 60 prostate carcinomas, 40 normal seminal vesicles, and 310 nonprostatic tumors. All nonprostatic tumors proved negative with both antibodies. However, 13 (32%) seminal vesicles showed immunoreactivity with polyclonal anti-PSA, but none showed immunoreactivity with the monoclonal antibody. The sensitivity of the 2 antibodies for prostate cancer varied with tumor grade. In Gleason pattern 3, both antibodies showed diffuse immunostaining in all cases. In Gleason pattern 5, polyclonal anti-PSA showed diffuse (>95%) tumor cell positivity in 18 cases (90%), while with the monoclonal antibody, 7 cases (35%) showed only focal (<10%) tumor cell immunoreactivity. Thus, monoclonal anti-PSA seems to be useful in small gland proliferations in which the differential diagnosis includes seminal vesicle, while for poorly differentiated neoplasms, polyclonal anti-PSA is considered superior. Sections of high-grade prostate cancer should be included as positive controls for PSA immunostaining.
Varma
Murali
M
Department of Pathology, University Hospital of Wales, Cardiff.
Morgan
Meleri
M
Jasani
Bharat
B
Tamboli
Pheroze
P
Amin
Mahul B
MB
D000906:Antibodies; D000911:Antibodies, Monoclonal; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D017430:Prostate-Specific Antigen / Q000032:analysis*; D011469:Prostatic Diseases / Q000175:diagnosis* / Q000473:pathology; D011471:Prostatic Neoplasms / Q000175:diagnosis; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
D000906:Antibodies; D000911:Antibodies, Monoclonal; D017430:Prostate-Specific Antigen