Although most of the patients in our study were pretreated with anti-ERBB2 agents, the CNS-related death rate was higher than that reported for other cancers.20 In a large, single-center study including more than 400 patients with solid tumors and brain metastasis in the clinical setting, only 10% of patients died of CNS-related causes.20 We believe that the significant discordance in ERBB2+ MBC is related to how this disease responds to systemic therapies in the extracranial compartment, resulting in a higher proportion of patients with disease confined to the brain. Here, ERBB2 is linked to cancer.