MKI67 and bone metastasis: Meanwhile, relevant variables that exhibited p-values less than 0.2 in the univariate analysis were exported into the multivariate regression model, including age, HER2 expression, Ki67 index, distant lymph nodes metastasis, brain metastasis, bone metastasis, liver metastasis, a history of radiation therapy, previous anti-HER2 treatment (TKIs or ADC), and treatment strategy (inetetamab + TKIs + chemotherapy).