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: 58/59 {negative in one poorly differentiated carcinoma}².

• 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)	100% (19/19)
prostatic adenocarcinoma, Gleeson 4/5	95% (strong in 90%)	70% (strong in 55%)
seminal vesicle	33% (13/40)	0/40
lung adenocarcinoma	0/40	0/40
breast adenocarcinoma	0/40	0/40
colonic adenocarcinoma	0/40	0/40

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.

©SMUHT/PW Bishop