Osteoprotegerin (OPG) and TNF-related apoptosis-inducing ligand (TRAIL) levels in malignant and benign pericardial effusions

ObjectivesOsteoprotegerin (OPG) is a regulator of bone and vascular homeostasis and acts as a decoy receptor for proapoptotic TNF-related apoptosis-inducing ligand (TRAIL).Design and methodsWe assessed pericardial and serum levels of OPG and TRAIL in pericardial effusions (PE) of malignant (mPE, n = 24) or non-malignant (nPE, n = 34) origin, and in pericardial fluid (PF, n = 25) of coronary artery disease (CAD) patients by ELISA.ResultsOPG was at least 5fold higher in PE or PF compared to serum, with a significantly higher ratio of pericardial to serum OPG in patients with mPE or nPE compared to PF (mPE vs. PF, p = 0.011; nPE vs. PF, p < 0.001). TRAIL was only detectable in mPE and PF. Logistic regression analysis revealed that a high ratio of pericardial to serum OPG and high TRAIL in PE were the best variable combination to predict malignancy of PE.ConclusionsPericardial and systemic OPG or TRAIL are potential diagnostic tools to discriminate between malignant or benign PE.

► Biomarkers to distinguish between malignant and benign pericardial effusions are urgently needed.
► OPG or TRAIL have not been assessed in pericardial effusions.
► Pericardial OPG is at least 5 times higher compared to systemic levels.
► A high ratio of pericardial to serum OPG and high TRAIL in PE were the best variable combination to predict malignancy of PE.