ERBB2 and bone metastasis: The incidence of bone metastasis in total patients of the HER2 IHC 1+ and IHC 0 group (12.7%) was significantly higher than that in the HER2 IHC 2+ group (4.7%) (p < 0.001), which suggested that for patients in the HER2 IHC 1+ and IHC 0 group, early screening of bone metastasis in breast cancer patients is important for early detection and early treatment of bone metastasis.