This increased RANKL and RANKL: OPG ratio is in line with observations in an in vitro study in three human NSCLC cell lines and in 127 NSCLC tumor samples (52 primary tumors and 75 bone metastasis samples) in which the expression of RANKL, RANK and OPG was estimated by RT-PCR in cell lines and by immunohistochemistry (IHC) on tumor tissue (16). This evidence concerns the gene TNFRSF11A and non-small cell lung carcinoma.