Survival upon a brain metastasis diagnosis is 4 months to 2 years, with worse prognosis for patients with triple negative (TN) breast cancer or multiple brain lesions, and better prognosis for those with oestrogen receptor-positive (ER+) or human epidermal growth factor receptor 2-positive (HER2+) disease or a single brain metastasis [2, 3]. The gene discussed is ERBB2; the disease is breast cancer.