%0 Journal Article
%T Prostate-specific antigen (PSA/hK3): a further player in the field of breast cancer diagnostics?
%A Ferdinando Mannello
%A Giancarlo Gazzanelli
%J Breast Cancer Research
%D 2001
%I BioMed Central
%R 10.1186/bcr302
%X Omnia, quae nunc vetustissima creduntur, nova fuere [All, which we consider now as most ancient, was new once]Tacitus, Annals, Book XI, 24As with everything else in science, biological research involves the continuous updating of physiological phenomena, sometimes subverting the certainty 'written in stone'. That is also true of prostate-specific antigen (PSA), an antigen discovered in the 1970s and introduced to urological practice about 15 years ago [1]. Although it is widely used as the most sensitive marker available so far for screening, diagnosis and monitoring human prostate cancer progression as well as response to therapy, discoveries over the past decade have unequivocally indicated that the original antigen PSA is no longer prostate-specific, shedding light on the multifunctional behaviour of this 'novel' serine protease [2]. The main characteristics of this kallikrein, which belongs to the family of serine proteases, have previously been described in detail [3] and are therefore mentioned only briefly here. The glandular kallikrein gene family is composed of three genes, localized on chromosome 19q13.3-q13.4; the KLK-3 gene locus encodes the extracellular serine protease PSA, which has also been named human glandular kallikrein 3 (hK3). In the prostate, PSA expression is localized to the differentiated, secretory columnar cells of the glandular epithelium. Biochemically, it is a 33 kDa single-chain glycoprotein with chymotrypsin-like activity that requires post-translational processing for its full proteolytic activity.Physiologically, PSA has a role in the dissolution of the gel structure of freshly ejaculated semen, through specific proteolysis of both high molecular mass semenogelin and fibronectin. In seminal fluid about two thirds of PSA is enzymically active, whereas the remainder is inactive and does not bind to protease inhibitors. Low levels of PSA are normally released into the blood and its predominant molecular form is that complexed with ¦Á1-
%K breast
%K breast cyst fluid
%K cancer
%K nipple aspirate fluid
%K prostate-specific antigen
%U http://breast-cancer-research.com/content/3/4/238