Immunotherapies are revolutionizing cancer care, producing majicontrast red 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 lock shock and barrel art 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.