ERBB2 and breast cancer: Our study found that the median age of patients with bone marrow metastases was 49.5 years old (29–68 years), the pathological type was invasive ductal carcinoma, the molecular type was HR positive/HER2 negative, the Ki-67 index was highly expressed, and histological grades 2–3 were more common, which is similar to the clinical features of breast cancer patients with BMM in a retrospective study by Abdullah Sakin et al.