Multiplexed targeted mass spectrometry assays for prostate cancer-associated urinary proteins

// Tujin Shi 1 , Sue-Ing Quek 2, 3, 6 , Yuqian Gao 1 , Carrie D. Nicora 1 , Song Nie 1 , Thomas L. Fillmore 4 , Tao Liu 1 , Karin D. Rodland 1 , Richard D. Smith 1 , Robin J. Leach 5 , Ian M. Thompson 5 , Elizabeth A. Vitello 2, 3 , William J. Ellis 2 , Alvin Y. Liu 2, 3 and Wei-Jun Qian 1 1 Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA 2 Department of Urology, University of Washington, Seattle, WA, USA 3 Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA 4 Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA 5 Department of Urology and the Cancer Therapy and Research Center, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA 6 Present address: Singapore Polytechnic, Center for Biomedical and Life Sciences T11A-412 (level 4), Singapore Correspondence to: Wei-Jun Qian, email: weijun.qian@pnnl.gov Alvin Y. Liu, email: aliu@uw.edu Keywords: secreted protein biomarkers; prostate cancer detection; prostate cancer; targeted mass spectrometry; selected reaction monitoring Received: May 05, 2017     Accepted: August 04, 2017     Published: October 09, 2017 ABSTRACT Biomarkers for effective early diagnosis and prognosis of prostate cancer are still lacking. Multiplexed assays for cancer-associated proteins could be useful for identifying biomarkers for cancer detection and stratification. Herein, we report the development of sensitive targeted mass spectrometry assays for simultaneous quantification of 10 prostate cancer-associated proteins in urine. The diagnostic utility of these markers was evaluated with an initial cohort of 20 clinical urine samples. Individual marker concentration was normalized against the measured urinary prostate-specific antigen level as a reference of prostate-specific secretion. The areas under the receiver-operating characteristic curves for the 10 proteins ranged from 0.75 for CXL14 to 0.87 for CEAM5. Furthermore, MMP9 level was found to be significantly higher in patients with high Gleason scores, suggesting a potential of MMP9 as a marker for risk level assessment. Taken together, our work illustrated the feasibility of accurate multiplexed measurements of low-abundance cancer-associated proteins in urine and provided a viable path forward for preclinical verification of candidate biomarkers for prostate cancer.