Serum bone turnover markers may be involved in the metastatic potential of lung cancer patients.

The aim of this study was to investigate several bone markers in Non-Small Cell Lung (NSCLC) and Small Cell Lung (SCLC) patients experiencing or not secondary bony disease. Fasting serum levels of bone formation, bone resorption, and osteoclastogenesis markers were determined in 22 NSCLC patients with bone metastases, 18 without bone metastasis, and 28 SCLC patients. A total of 29 healthy volunteers were also included in the study. Decreased osteocalcin (OC) serum levels and increased osteopontin and ligand of the receptor of nuclear factor kB (RANKL) serum levels were detected in NCSLC patients with bone metastases while increased C-terminal cross-linking telopeptide of type I collagen and increased RANKL/OPG (osteoprotegerin) ratio were detected in SCLC patients. Increased serum levels of OPG were observed in all lung cancer patients. OPG may be actively involved in the development of lung cancer metastasis. Furthermore, OC, OPN, and RANKL in NSCLC and CTX and RANKL in SCLC patients may also have a broader role in the pathogenesis and spread of lung cancer. They also provide useful information in identifying the group of patients that may benefit from a more rigorous treatment.