title: Novel immunoassay for the measurement of complexed prostate-specific antigen in serum.
abstract: Serum prostate-specific antigen (PSA) is an effective diagnostic tool for detection of prostate cancer (CaP) at an early and potentially curable stage, but specificity is low. Studies have shown that the proportion of serum PSA complexed with alpha-1-antichymotrypsin (ACT) is higher in men with CaP than in men with benign prostate disease. We developed a novel immunoassay for complexed PSA based on the unique binding properties of a monoclonal antibody that fails to bind free PSA in the presence of antibodies specific for free PSA. The assay measured mixtures of free and complexed PSA accurately, and the measured values of free + complexed PSA in artificial mixtures and in patient sera were equivalent to the measured value of total PSA. Both the serum concentration and the proportion of complexed PSA was substantially higher in patients with CaP compared with patients with benign prostate disease. The cPSA assay may have utility in improving specificity in screening for prostate cancer.
authors.affiliation: Bayer Corporation, Business Group Diagnostics, Tarytown, NY 10591, USA. jeffrey.allard.b@bayer.com
authors.forename: W J
authors.initials: WJ
authors.lastname: Allard
authors.forename: Z
authors.initials: Z
authors.lastname: Zhou
authors.forename: K K
authors.initials: KK
authors.lastname: Yeung
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008297:Male; D017430:Prostate-Specific Antigen / Q000097:blood* / Q000276:immunology / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000097:blood* / Q000378:metabolism / Q000473:pathology; D011480:Protease Inhibitors / Q000097:blood / Q000378:metabolism; D011485:Protein Binding; D012680:Sensitivity and Specificity
chemical_list: D000911:Antibodies, Monoclonal; D011480:Protease Inhibitors; D017430:Prostate-Specific Antigen