ERBB2 and breast carcinoma: In the training cohort, the univariate Cox proportional hazards regression analysis showed that age, race, primary site, grade, radiotherapy, surgery, chemotherapy, liver metastasis, lung metastasis, brain metastasis, breast cancer subtype, HER2 status, insurance status, and marital status were prognostic factors (all P < 0.05) (Table 5).