Rj. Ablin, A RETROSPECTIVE AND PROSPECTIVE OVERVIEW OF PROSTATE-SPECIFIC ANTIGEN, Journal of cancer research and clinical oncology, 123(11-12), 1997, pp. 583-594
Since the identification of prostate-specific antigen (PSA), continued
technological advances have provided highly sensitive assays for its
quantification. Given its lack of disease specificity, and its recent
detection at low levels in an increasing number of non-prostatic tissu
es, PSA is far from being the perfect ''tumour'' marker (biological ma
rker). However, the positive predictive value of PSA for assessing can
cer risk makes PSA the most useful ''tumour'' marker for monitoring pr
ogression and response to treatment among patients with prostate cance
r. Earlier detection through screening for elevated levels of PSA, whi
le controversial, has been proposed as a way to decrease prostate canc
er mortality. Haematogenous identification of PSA mRNA may provide sta
ge-related prognostic information, and the use of ultrasensitive assay
s for PSA may permit earlier identification of residual or recurrent c
ancer, following treatment and the initiation of adjuvant therapy. Var
ious PSA-related concepts, including the ratio of ''free'' PSA and com
plexes of PSA with the protease inhibitor, alpha(1)-antichymotrypsin,
to total PSA, have been proposed and placed within diagnostic and mana
gement algorithms. Elevations of PSA in other irregularities of the pr
ostate, notably in benign prostatic hyperplasia, and the increasing fr
equency and number of non-prostatic tissues, including those in women,
expressing PSA, have implications for future immunoassays for PSA and
strategies for immunotherapy using PSA-based monoclonal antibodies or
vaccines, as well as for the molecular basis for its anomalous expres
sion and physiological function(s).