Background: The diagnosis of malignant pleural effusion (MPE) remains a common clinical challenge because of the sensitivity of conventional cytology for the detection is insufficient. Thus, a sensitive clinical marker for diagnosis is required. The aim of this study was to assess the role of two anti-angiogenic cytokines, soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) and endostatin, in diagnosing MPE.
Methods: Effusion samples from 44 patients with MPE caused by lung cancer and from 36 patients with benign pleural effusion (BPE) were collected. The concentrations of sVEGFR-1 and endostatin in pleural fluid were determined by an enzyme-linked immunosorbent assay (ELISA). The diagnostic performance was measured by receiver operating characteristic curves (ROCs).
Results: The levels of sVEGFR-1 and endostatin in MPE due to lung cancer were significantly higher than those in BPE (p < 0.05). The sensitivity and specificity of endostatin were 52.27% and 86.11%, respectively, while for sVEGFR-1, the sensitivity was 88.64% and the specificity was 58.33%. Interestingly, the combination of sVEGFR1 and endostatin produced better sensitivity and specificity of 72.73% and 83.33%, respectively. In addition, the levels of sVEGFR-1 and endostatin were significantly related to each other (p < 0.05), and the levels of endostatin in bloody effusions were significantly higher than those in non-bloody effusions (p < 0.05).
Conclusions: Our study indicated that the levels of sVEGFR-1 and endostatin were significantly elevated in MPE. The combined detection of sVEGFR-1 and endostatin may be useful in the diagnosis of MPE.