The asbestos-related malignancy, malignant pleural mesothelioma (MPM), is often detected in late stages with little chance for survival. Biomarkers are needed to (1)determine which patients have been asbestos exposed (AE) (2) distinguish AE and non-MPM malignancies from MPM patients and (3) determine which MPM patients are at highest risk for early recurrence or death. The EDRN Mesothelioma Biomarker Discovery Laboratory will refine and validate three novel MPM blood/effusion based markers (FBLN3, SOMAmer 13 classifier, HMGB1 Isoforms) and investigate whether immune- oncologic gene expression differences in the cellular component of the circulating blood microenvironment can stratify AE and MPM from other control cohorts. All of these in Phase I/II discovery studies have yielded AUCs > 0.9. An in-house, novel Luminex based assay (Soma 14 NYU MPM) consisting of 13 slow-off-rate-modified-aptamers (SOMAmers) and a newly constructed FBLN3 SOMAmer will be assembled and technically validated using identical specimens that were used to discover these 14 analytes. Diagnostic and prognostic capabilities in both plasma and pleural effusion will be performed with healthy, non-AE exposed, AE, MPM, and non- MPM cancer cohorts, followed by a blinded validation in specimens provided by the Princess Margaret Cancer Center. The University of Hawaii/Cedar Sinai Medical Center, using 202 NYU pleural effusions, will evaluate a unique, technically validated, electrospray ionization liquid chromatography tandem mass spectrometry assay for HMGB1 and its isoforms to differentiate MPM from non-MPM benign and malignant effusions. The HMGB1 effusion results will be compared to those obtained with the Soma 14 NYU MPM using validation cohorts from an approved EDRN MPM screening program in Santiago, Chile and South Glasgow University Hospital. Finally we will refine and validate our buffy coat/PBMC MPM profile of 5 immuno- oncology genes which in Phase II studies can separate non AE individuals vs AE individuals vs MPM with AUCs of 1.0. These studies could lead to 3 novel platforms which individually or combined could significantly improve chances for early diagnosis and accurate prognostication of patients with MPM.