RUNX2 and breast cancer: Also, we found that the presence of RUNX2 (Runt-related transcription factor 2)- and RANKL (receptor activator of nuclear factor κΒ ligand)-positive BOLCs in primary tumour correlated with the development of bone metastasis.5 Starting from these evidences, the aim of this study was to investigate the relationship between the expression of the main prognostic and predictive in situ markers of breast cancer and the presence of BOLCs at the primary lesion sites.