Prognostic Value of Osteoprotegerin and sRANKL in Bronchoalveolar Lavage Fluid of Patients with Advanced Non-small Cell Lung Cancer

Osteoprotegerin (OPG) is a soluble decoy receptor for receptor activator of nuclear factor-kappa B ligand (sRANKL). OPG promotes endothelial cell survival and neoangiogenesis. Dysregulation of the OPG/RANKL system has been detected in several tumors. In the present study, we evaluated the clinical usefulness of OPG and sRANKL assessment in bronchoalveolar lavage fluid (BALF) of patients with advanced non-small cell lung cancer (NSCLC). We measured the concentration of OPG and sRANKL in BALF of 44 NSCLC patients and 15 healthy volunteers taken as control subjects. The OPG content was higher in the NSCLC group than that in controls [0.48 (0.12–1.45) vs. 0.23 (0.14–0.75) pmol/l; p = 0.0001]. There were no significant differences in sRANKL content between the NSCLC and control groups [1.22 (0.74–23.00) vs. 1.12 (0.79–4.39) pmol/l; p = 0.67]. However, we found that the greater the level of sRANKL in NSCLC patients, the shorter the overall survival. We found a correlation between the content of sRANKL and the percentage of lymphocytes in BALF of NSCLC patients (r = 0.52; p = 0.041). We conclude that NSCLC patients have a higher content of OPG in BALF than healthy people. A high level of sRANKL in BALF of NSCLC patients may predict worse survival.