Immunotherapies are revolutionizing cancer care, producing durable responses and potentially cures in a subset of patients. However, response rates are low for most tumors, grade 3/4 toxicities are not uncommon, and our current understanding of tumor immunobiology is incomplete. While hundreds of immunomodulatory proteins in the tumor microenvironment shape the anti-tumor response, few of them can be reliably quantified. To address this need, we developed a multiplex panel of targeted proteomic assays targeting 52 peptides representing 46 proteins using peptide immunoaffinity enrichment coupled to multiple reaction monitoring-mass spectrometry. We validated the assays in tissue and plasma matrices, where performance figures of merit showed over 3 orders of dynamic range and median inter-day CVs of 5.2% (tissue) and 21% (plasma). A feasibility study in clinical biospecimens showed detection of 48/52 peptides in frozen tissue and 38/52 peptides in plasma. The assays are publicly available as a resource for the research community.
Keywords: cancer; correlative biomarkers; immuno-MRM; immunotherapy; mass spectrometry.
Copyright © 2021 Whiteaker, Lundeen, Zhao, Schoenherr, Burian, Huang, Voytovich, Wang, Kennedy, Ivey, Lin, Murillo, Lorentzen, Thiagarajan, Colantonio, Caceres, Roberts, Knotts, Reading, Kaczmarczyk, Richardson, Garcia-Buntley, Bocik, Hewitt, Murray, Do, Brophy, Wilz, Yu, Ajjarapu, Boja, Hiltke, Rodriguez and Paulovich.