Prostate-specific antigen (PSA)

Immunohistochemical expression

the epithelial cells of the acini and ducts of the prostatic gland
urothelium of the bladder, urethra, periurethral glands and urachal remnant
seminal vesicles, using polyclonal antibody1.
endometrium
anal mucosa and glands
ductal cells of the pancreas
normal salivary gland
neutrophils
prostatic carcinoma: high grade tumours may be negative: 58/592.
adenocarcinoma of the urethra and periurethral glands
extramammary Paget's disease of the penis
pleomorphic adenoma and carcinoma of the salivary gland
some neuroendocrine tumours
The monoclonal antibody shows greater specificity but the polyclonal antibody shows greater sensitivity1:

	polyclonal antibody (Dako A0562)	monoclonal antibody (Dako ER/PR8)
prostatic adenocarcinoma, Gleeson 3	100% (19/19)1	100% (19/19)1
prostatic adenocarcinoma, Gleeson 4/5	95% (strong in 90%)1	70% (strong in 55%)1
seminal vesicle	33% (13/40)1	0/401
lung adenocarcinoma	0/401	0/401
breast adenocarcinoma	0/401	0/401
colonic adenocarcinoma	0/401	0/401

	ER/PR8
breast, adenocarcinomas	0/353
ovary, serous	0/183
ovary, mucinous	1/103
endometrial adenocarcinomas	1/103
pancreas, adenocarcinomas	0/533
ampulla of Vater, adenocarcinomas	0/63
cholangiocarcinoma	0/103
oesophagus, adenocarcinoma	0/213
oesophagus, squamous cell carcinoma	0/73
stomach, adenocarcinomas	1/343
colon, adenocarcinomas	0/473
prostate, adenocarcinomas	18/183
lung, adenocarcinoma	0/463
lung, small cell carcinoma	0/33
lung, squamous cell carcinoma	0/73
mesothelioma	0/63
renal cell carcinoma	0/153
hepatocellular carcinoma	0/63

Rarely, pulmonary small cell carcinoma may produce ectopic prostate specific antigen and prostatic acid phosphatase4.

Negative in:

transitional cell carcinoma of bladder: 0/282.

Diagnostic utility

identification of metastatic adenocarcinoma of the prostate: use in conjunction with prostatic acid phosphatase, CK7, CK 20 (usual profile CK7-/CK20-) and CD 57.
diagnosis and monitoring of prostatic carcinoma by assaying serum levels

References

1 M Morgan et al. Sensitivity and specificity of PSA Immunohistochemistry: a detailed comparison of monoclonal and polyclonal antibodies. Abstract 184, Pathological Society of Great Britain and Ireland January 2001.

2Bassily, N.H., Vallorosi, C.J., Akdas, G., Montie, J.E. and Rubin, M.A. Coordinate expression of cytokeratins 7 and 20 in prostate adenocarcinoma and bladder urothelial carcinoma. Am J Clin Pathol 2000;113:383-8.

3 Dennis JL, Hvidsten TR, Wit EC, et al. Markers of adenocarcinoma characteristic of the site of origin: development of a diagnostic algorithm. Clin Cancer Res 2005; 11:3766-72 FULL TEXT

4 Freeman NJ,Doolittle C. Elevated prostate markers in metastatic small cell carcinoma of unknown primary. Cancer 1991; 68:1118-20