Clinical and pathological characteristics potentially influencing bone metastasis-including age, menopausal status, histological grade, affected side, maximum tumor diameter, lymph node staging, TNM staging, ER status, PR status, HER-2 status, Ki-67, molecular subtypes, vascular tumor thrombus, nerve infiltration and visceral metastasis-were collected. The gene discussed is PGR; the disease is bone metastasis.