Diagnostic value of interleukine-6, transforming growth factor-beta 1 and vascular endothelial growth factor in malignant pleural effusions

SummaryStudy objectivesWe evaluate the accuracy of pleural interleukine-6 (IL-6), transforming growth factor-beta 1 (TGF-β1), and vascular endothelial growth factor (VEGF) levels for differentiating benign from malignant pleural exudates.Patients and methodsLevels of IL-6, TGF-β1, and VEGF were measured by ELISA in 103 patients with non neutrophilic (<50%) exudative pleurisy including both benign and malignant effusions. Pleurisies were splitted into benign and malignant according to the pathological diagnosis.ResultsThirty-nine benign (seven infections; 32 inflammatory diseases) and 64 malignant (34 extrathoracic tumors; 25 lung cancers; five mesotheliomas) pleural exudates were diagnosed by thoracoscopy. Pleural reticulo-monocyte count, protein Light's ratio and lactic dehydrogenase Light's ratio were significantly higher in malignant than in benign effusions (p < 0.05, p < 0.001 and p < 0.001, respectively). The median (range) level of VEGF was significantly higher in malignant than in benign effusions (664.50 pg/ml [10–40,143] vs 349 pg/ml [10–8888]) (p < 0.05). VEGF levels correlated with pleural LDH (r = 0.41, p < 0.0001), glucose (r = −0.30, p < 0.01) and red cell count (r = 0.57, p < 0.0001).No significant difference was found between malignant and benign effusions with respect to IL-6 (26.8 ng/ml [1.8–421] vs 18.4 ng/ml [0.45–400], respectively) and TGF-β1 (1079 pg/ml [18–6206] vs 1123 pg/ml [34–5447]) levels.ROC analysis between benign and malignant pleurisies for VEGF showed an area under the curve of 619 (p = 0.03) with a value of 382 pg/ml as the best threshold for distinguishing benign from malignant effusions.ConclusionsMalignant effusions may enhance the release of VEGF in pleural space and its measurement may help in the diagnosis of malignant effusion.