This compares with 18.8%, 25.5% and 17.7% of patients in the whole ESME database and with 16.6%, 26.4% and 19.5% in a series of 11 011 unselected stage I–III breast cancer patients.40 These proportions in patients with CNS metastases are consistent with previous data for HR-negative19,35,36,41,42 and triple-negative tumours,15,21,41,42 but not for HER2-positive tumours. The gene discussed is ERBB2; the disease is breast carcinoma.