Quantitation of serum prostate-specific membrane antigen by a novel protein biochip immunoassay discriminates benign from malignant prostate disease

• Published in: Cancer research (Chicago, Ill.) Vol. 61; no. 16; pp. 6029 - 6033
• Main Authors: ZHEN XIAO, ADAM, Bao-Ling, CAZARES, Lisa H, CLEMENTS, Mary Ann, DAVIS, John W, SCHELLHAMMER, Paul F, DALMASSO, Enrique A, WRIGHT, George L
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Association for Cancer Research 15.08.2001
• Subjects: Adult; Aged; Aged, 80 and over; Antibodies, Monoclonal; Antigens, Neoplasm - blood; Antigens, Surface; Biological and medical sciences; Carboxypeptidases - blood; Diagnosis, Differential; Feasibility Studies; Glutamate Carboxypeptidase II; Humans; Immunoassay - methods; Male; Mass Spectrometry - methods; Medical sciences; Middle Aged; Nephrology. Urinary tract diseases; Prostatic Hyperplasia - diagnosis; Prostatic Hyperplasia - immunology; Prostatic Neoplasms - diagnosis; Prostatic Neoplasms - immunology; Tumors of the urinary system; Urinary tract. Prostate gland; Human; Urinary system disease; Prostate disease; Tumor associated antigen; Methodology; Hyperplasia; Biological marker; Malignant tumor; Enzyme immunoassay; In vitro; Protein; Investigation method; Serum; Prostatitis; Diagnosis; Benign neoplasm; Prostate specific membrane antigen; Male genital diseases; Prostate; Quantitative analysis
• ISSN: 0008-5472; 1538-7445

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.