SPP1 and breast cancer: It’s not a coincidence that Bellahcène et al. using polyclonal antibodies and immunoperoxidase techniques, identified three bone matrix proteins, namely OPN, OSN, and BSP, which were synthesized by cells with osteoblastic linage and were expressed in human breast cancers, highlighting the importance of bone matrix mineralization in breast carcinogenesis while BSP was postulated to initiate hydroxyapatite formation16,17.