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

Abstract

Osteoprotegerin (OPG) is a regulator of bone and vascular homeostasis and acts as a decoy receptor for proapoptotic TNF-related apoptosis-inducing ligand (TRAIL). We 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. OPG was at least 5 fold 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. Pericardial and systemic OPG or TRAIL are potential diagnostic tools to discriminate between malignant or benign PE.