Pleural effusion, an accumulation of pleural fluid, contains
proteins originating from plasma filtrate and, especially when tissues are damaged, parenchymal interstitial spaces of lungs and/or other organs. This report presents data of the first global proteomic analysis of human
pleural effusion. A composite sample was prepared by pooling
pleural effusions from seven
lung adenocarcinoma patients. Two-dimensional gel electrophoresis analysis of the composite sample revealed 472
silver-stained spots. 242 selected gel spots were subjected to
protein identification by in-gel digestion, liquid chromatography-tandem mass spectrometry, and sequence database search. 44
proteins were identified with higher confidence levels (at least two unique
peptide sequences matched), while 161 other
proteins were identified at the minimal confidence level (only one unique
peptide sequence matched). The data provide fundamental information on the composition of
protein contents in human
pleural effusion. Among these 44
proteins that were identified with higher confidence levels, 7
proteins,
retinoblastoma binding protein 7, synaptic vesicle
membrane protein,
corticosteroid binding globulin precursor, PR-domain containing
protein 11, envelope
glycoprotein, MSIP043
protein, and
titin have not been reported in plasma and may represent
proteins specifically present in
pleural effusion. These
proteins could have originated from parenchymal interstitial spaces and represent potential candidates of useful
biomarkers that could not be readily detected in plasma but in
pleural effusion.
Retinoblastoma binding protein 7 is of special interest since it may play a role in the regulation of cell proliferation and differentiation.