<b>Results:</b> The multivariate logistic regression analysis revealed that histological grade (<i>p</i> = 0.002), progesterone receptor (PR) negativity (<i>p</i> = 0.001), human epidermal growth factor receptor 2 (HER-2) negativity (<i>p</i> = 0.002) and visceral metastasis (<i>p</i> < 0.001) were identified as independent predictors of bone metastasis in breast cancer. The gene discussed is PGR; the disease is breast cancer.