title: Analysis of serum total and free PSA using immunoaffinity depletion coupled to SRM: correlation with clinical immunoassay tests.
abstract: Recently, selected reaction monitoring mass spectrometry (SRM-MS) has been more frequently applied to measure low abundance biomarker candidates in tissues and biofluids, owing to its high sensitivity and specificity, simplicity of assay configuration, and exceptional multiplexing capability. In this study, we report for the first time the development of immunoaffinity depletion-based workflows and SRM-MS assays that enable sensitive and accurate quantification of total and free prostate-specific antigen (PSA) in serum without the requirement for specific PSA antibodies. Low ng/mL level detection of both total and free PSA was consistently achieved in both PSA-spiked female serum samples and actual patient serum samples. Moreover, comparison of the results obtained when SRM PSA assays and conventional immunoassays were applied to the same samples showed good correlation in several independent clinical serum sample sets. These results demonstrate that the workflows and SRM assays developed here provide an attractive alternative for reliably measuring candidate biomarkers in human blood, without the need to develop affinity reagents. Furthermore, the simultaneous measurement of multiple biomarkers, including the free and bound forms of PSA, can be performed in a single multiplexed analysis using high-resolution liquid chromatographic separation coupled with SRM-MS. This article is part of a Special Issue entitled: Translational Proteomics.
authors: Biological Sciences Division, Pacific Northwest National Laboratory, United States.
authors: Tao
authors: T
authors: Liu
authors: Mahmud
authors: M
authors: Hossain
authors: Athena A
authors: AA
authors: Schepmoes
authors: Thomas L
authors: TL
authors: Fillmore
authors: Lori J
authors: LJ
authors: Sokoll
authors: Scott R
authors: SR
authors: Kronewitter
authors: Grant
authors: G
authors: Izmirlian
authors: Tujin
authors: T
authors: Shi
authors: Wei-Jun
authors: WJ
authors: Qian
authors: Robin J
authors: RJ
authors: Leach
authors: Ian M
authors: IM
authors: Thompson
authors: Daniel W
authors: DW
authors: Chan
authors: Richard D
authors: RD
authors: Smith
authors: Jacob
authors: J
authors: Kagan
authors: Sudhir
authors: S
authors: Srivastava
authors: Karin D
authors: KD
authors: Rodland
authors: David G
authors: DG
authors: Camp
mesh_terms: D001681:Biological Assay / Q000379:methods; D014408:Biomarkers, Tumor / Q000097:blood*; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods; D008297:Male; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood*; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen