BACKGROUND: The aim of this study was to develop a method to separate and quantify subforms of free prostate-specific antigen (fPSA) in serum by two-dimensional electrophoresis and to assess the diagnostic accuracy of these subforms for prostate cancer (PCa) diagnosis in comparison with total PSA (tPSA) and the ratio of fPSA to tPSA (%fPSA). METHODS: Sera from 50 patients with and without PCa, respectively, were studied. PSA was isolated by immunoadsorption on streptavidin-coated magnetic beads with biotinylated anti-PSA antibodies and separated by two-dimensional electrophoresis. After semidry blotting, the intensities of the fPSA spots were quantified by chemiluminescence using an imager analyzer. RESULTS: The method detected subforms to a concentration of 0.1 mug/L fPSA with an imprecision (CV) <16%. We detected 15 immunoreactive fPSA spots of different intensities. Spots F2 and F3 were present in all samples. F2 was lower in samples from non-PCa patients (median, 23%) than in samples from PCa patients (49%), whereas F3 behaved inversely (non-PCa, 73%; PCa, 45%). Ratios of F2 to F3 and F2/F3 to %fPSA, respectively, showed improved diagnostic accuracy compared with tPSA and %fPSA. Better differentiation by F2/F3 or by F2/F3 to %fPSA was particularly evident in patients with %fPSA values >15%. There were no associations between the PCa grading scale and fPSA subforms. CONCLUSIONS: fPSA subforms separated by two-dimensional electrophoresis may improve both sensitivity and specificity in prostate cancer diagnostics compared with tPSA and %fPSA. The development of a practicable assay based on the immunologic properties of these different fPSA subforms seems to be promising.
BACKGROUND: The aim of this study was to develop a method to separate and quantify subforms of free prostate-specific antigen (fPSA) in serum by two-dimensional electrophoresis and to assess the diagnostic accuracy of these subforms for prostate cancer (PCa) diagnosis in comparison with total PSA (tPSA) and the ratio of fPSA to tPSA (%fPSA). METHODS: Sera from 50 patients with and without PCa, respectively, were studied. PSA was isolated by immunoadsorption on streptavidin-coated magnetic beads with biotinylated anti-PSA antibodies and separated by two-dimensional electrophoresis. After semidry blotting, the intensities of the fPSA spots were quantified by chemiluminescence using an imager analyzer. RESULTS: The method detected subforms to a concentration of 0.1 mug/L fPSA with an imprecision (CV) <16%. We detected 15 immunoreactive fPSA spots of different intensities. Spots F2 and F3 were present in all samples. F2 was lower in samples from non-PCa patients (median, 23%) than in samples from PCa patients (49%), whereas F3 behaved inversely (non-PCa, 73%; PCa, 45%). Ratios of F2 to F3 and F2/F3 to %fPSA, respectively, showed improved diagnostic accuracy compared with tPSA and %fPSA. Better differentiation by F2/F3 or by F2/F3 to %fPSA was particularly evident in patients with %fPSA values >15%. There were no associations between the PCa grading scale and fPSA subforms. CONCLUSIONS: fPSA subforms separated by two-dimensional electrophoresis may improve both sensitivity and specificity in prostate cancer diagnostics compared with tPSA and %fPSA. The development of a practicable assay based on the immunologic properties of these different fPSA subforms seems to be promising.
Authors: Akos Végvári; Melinda Rezeli; Jari Häkkinen; Carina Sihlbom; Elisabet Carlsohn; Johan Malm; Hans Lilja; Thomas Laurell; György Marko-Varga Journal: J Proteomics Date: 2011-06-23 Impact factor: 4.044
Authors: Esther Llop; Montserrat Ferrer-Batallé; Sílvia Barrabés; Pedro Enrique Guerrero; Manel Ramírez; Radka Saldova; Pauline M Rudd; Rosa N Aleixandre; Josep Comet; Rafael de Llorens; Rosa Peracaula Journal: Theranostics Date: 2016-05-24 Impact factor: 11.556