Vascular endothelial growth factor and protein level in pleural effusion for differentiating malignant from benign pleural effusion

Pleural effusion is associated with multiple benign and malignant conditions. Currently no biomarkers differentiate malignant pleural effusion (MPE) and benign pleural effusion (BPE) sensitively and specifically. The present study identified a novel combination of biomarkers in pleural effusion for differentiating MPE from BPE by enrolling 75 patients, 34 with BPE and 41 with MPE. The levels of lactate dehydrogenase, glucose, protein, and total cell, neutrophil, monocyte and lymphocyte counts in the pleural effusion were measured. The concentrations of interleukin (IL)-1β, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, tumor necrosis factor-α, interferon γ, transforming growth factor-β1, colony stimulating factor 2, monocyte chemoattractant protein-1 and vascular endothelial growth factor (VEGF) were detected using cytometric bead arrays. Protein and VEGF levels differed significantly between patients with BPE and those with MPE. The optimal cutoff value of VEGF and protein was 214 pg/ml and 3.35 g/dl respectively, according to the receiver operating characteristic curve. A combination of VEGF >214 pg/ml and protein >3.35 g/dl in pleural effusion presented a sensitivity of 92.6% and an accuracy of 78.6% for MPE, but was not associated with a decreased survival rate. These results suggested that this novel combination strategy may provide useful biomarkers for predicting MPE and facilitating early diagnosis.