TNFSF11 and breast cancer: Another successful approach has recently been reported by Cuyas et al. for aggressive forms of breast cancer: they showed that in breast cancer, a dysregulation of the OPG/RANK/RANKL signalling axis is present and is associated with the presence of CSCs’ highly expressing RANK, residing in the pre-metastatic niche and able to initiate metastasis including bone lesions [47,48,49].