Updated project metadata. We screened pleural effusion proteomes of mesothelioma and lung adenocarcinoma patients to identify novel soluble mesothelioma biomarkers. We performed quantitative mass spectrometry-(MS-) based proteomics using isobaric tags for relative and absolute quantification (iTRAQ) and used narrow range immobilized pH gradient/high resolution isoelectric focusing (IPG/HiRIEF; pH 4 to 4.25) prior to analysis by nano liquid chromatography-coupled MS/MS. Pleural effusions from patients with malignant mesothelioma (n=6), lung adenocarcinoma (n=6), or benign mesotheliosis (n=7) were analyzed, and more than 1,300 proteins were identified.