Compared with all patients in the cohort, those with HER2 mutations had no distinguishing clinical characteristics, including age at diagnosis of metastatic disease, diagnosis as metastatic recurrence versus de novo metastatic disease, presence of visceral versus bone-only metastases, or prior adjuvant treatment including aromatase inhibitors (Table 1). The gene discussed is CYP19A1; the disease is metastatic neoplasm.