Immunocytochemical Localisation of Prostate‐specific Antigen: Specificity and Application to Clinical Practice

Abstract

An immunocytochemical method to localise prostate-specific antigen (PSA) in paraffin sections was used to establish the prostatic origin of both primary and metastatic tumours. The specificity of the technique was confirmed in 65 known primary (63 PSA-positive) and 17 metastatic prostatic carcinomas (16 PSA-positive). Thirteen non-prostatic primary carcinomas and a series of benign proliferative and malignant conditions which might be considered in the morphological differential diagnosis of prostatic adenocarcinoma were PSA-negative. The technique has now been applied diagnostically to tumour tissue resected from 21 patients. These neoplasms of the base and neck of the bladder could not be categorised as prostatic or urothelial in origin by clinical and endoscopic assessment or by conventional histopathology. In 11 patients such tumours were PSA-positive, indicating a prostatic origin. In two further patients, the prostatic origin of lymph node secondaries was confirmed in the absence of a clinically apparent primary. The technique is a valuable adjunct to conventional histopathology.

Immunohistochemical pitfalls in prostate pathology

“…In our experience, PSA is very sensitive and labels 95% of poorly differentiated prostatic adenocarcinomas. Moreover, in our study, PSA is more sensitive than PSAP, although some studies have shown opposite results [30,31]. The staining pattern for PSA and PSAP is cytoplasmic and granular with sometimes luminal accentuation.…”

Direct cancer tissue proteomics: a method to identify candidate cancer biomarkers from formalin-fixed paraffin-embedded archival tissues

“…These results demonstrate that a known biomarker protein such as PSA can be sensitively quantified in needle-biopsy samples of cancer tissue. However, it is known that serum PSA levels do not always predict the presence of prostate cancers (Ford et al, 1985;Coombs et al, 1998;Gupta et al, 2004). It is anticipated that proteomic techniques can provide the identification of additional protein biomarkers that may be used in conjunction with PSA to increase the specificity and sensitivity in prostate cancer detection.…”

Prostate‐specific membrane antigen (PSMA) protein expression in normal and neoplastic tissues and its sensitivity and specificity in prostate adenocarcinoma: an immunohistochemical study using mutiple tumour tissue microarray technique

“…3,4 Most PaC cases show immunoreactivity for PSA and PAP, but this reactivity varies considerably with tumour grade and post-therapy status. 7,8 In well-differentiated PaC, the positivity for both markers is 100%. However, in poorly differentiated PaC, PSA positivity drops to 85% and PAP to 95%.…”

“…However, in poorly differentiated PaC, PSA positivity drops to 85% and PAP to 95%. [7][8][9] Nevertheless, some authors have reported that expression of these two markers might be lacking in 5% of high-grade PaC and in metastatic disease. 8 Others have shown that they might be reduced in expression in some treated cases.…”