ERBB2 and cancer: Five patients were excluded due to a prior or concomitant second malignant neoplasm without pathologic confirmation of brain metastasis, 11 due to discordant primary metastatic ERBB2 status or 1 ERBB2-negative metastatic site and no receipt of anti-ERBB2 therapy for metastasis, and 3 due to having no clinical data regarding local and systemic therapies and no details of their disease distribution.