title: Quantitation of serum prostate-specific membrane antigen by a novel protein biochip immunoassay discriminates benign from malignant prostate disease.
abstract: The lack of a sensitive immunoassay for quantitating serum prostate-specific membrane antigen (PSMA) hinders its clinical utility as a diagnostic/prognostic biomarker. An innovative protein biochip immunoassay was used to quantitate and compare serum PSMA levels in healthy men and patients with either benign or malignant prostate disease. PSMA was captured from serum by anti-PSMA antibody bound to ProteinChip arrays, the captured PSMA detected by surface-enhanced laser desorption/ionization mass spectrometry, and quantitated by comparing the mass signal integrals to a standard curve established using purified recombinant PSMA. The average serum PSMA value for prostate cancer (623.1 ng/ml) was significantly different (P < 0.001) from that for benign prostate hyperplasia (117.1 ng/ml) and the normal groups (age <50, 272.9 ng/ml; age >50, 359.4 ng/ml). These initial results suggest that serum PSMA may be a more effective biomarker than prostate-specific antigen for differentiating benign from malignant prostate disease and warrants additional evaluation of the surface-enhanced laser desorption/ionization PSMA immunoassay to determine its diagnostic utility.
authors.affiliation: Department of Microbiology, Eastern Virginia Medical School, Norfolk, Virginia 23507, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Xiao
authors.forename: B L
authors.initials: BL
authors.lastname: Adam
authors.forename: L H
authors.initials: LH
authors.lastname: Cazares
authors.forename: M A
authors.initials: MA
authors.lastname: Clements
authors.forename: J W
authors.initials: JW
authors.lastname: Davis
authors.forename: P F
authors.initials: PF
authors.lastname: Schellhammer
authors.forename: E A
authors.initials: EA
authors.lastname: Dalmasso
authors.forename: G L
authors.initials: GL
authors.lastname: Wright
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000097:blood*; D000954:Antigens, Surface; D002268:Carboxypeptidases / Q000097:blood*; D003937:Diagnosis, Differential; D005240:Feasibility Studies; D043425:Glutamate Carboxypeptidase II; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D008875:Middle Aged; D011470:Prostatic Hyperplasia / Q000175:diagnosis / Q000276:immunology*; D011471:Prostatic Neoplasms / Q000175:diagnosis / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D000954:Antigens, Surface; D002268:Carboxypeptidases; C473848:FOLH1 protein, human; D043425:Glutamate Carboxypeptidase II