ERBB2 and metastasis: It was denoted that the prognosis of HR + /HER2 + breast cancer patients were superior to that of HR−/HER2 + breast cancer presenting with visceral metastasis (P < 0.0001), lung-only disease (P = 0.00012), and brain involvement (P = 0.0048), while no significant difference was exhibited in patients between the two subgroups with bone-only metastasis, liver-only metastasis, and brain-only metastasis.