NFKB1 and breast cancer: Therefore, we speculated that overexpressing induced M-CSF and GM-CSF expression via activation of NF-κB signaling, and circIKBKB-induced M-CSF and GM-CSF might feeded back to further strengthen the circIKBKB-mediated NF-κB activation, which led to osteoclastogenesis and breast cancer bone metastasis.