Kerui Wu et al. found that regulating mir-19A expression in breast cancer cells did not change its growth or migration ability in vitro, but after being wrapped and released by Exos, integrin-binding Sialoprotein (IBSP) can attract osteoclasts and aggregate in the bone, becoming an osteoclast rich environment, and assist exosomal miR-19a to be delivered to osteoclasts to induce osteoclast formation, promoting The formation of PMN, enhancing bone metastasis in ER+ BC [73]. The gene discussed is IBSP; the disease is breast carcinoma.