We now recognise a novel taxonomy of breast cancer which classifies four distinct clinically relevant molecular subtypes, i.e., Luminal A breast cancer (LABC), Luminal B breast cancer (LBBC), human epidermal growth factor Receptor-2-enriched breast cancer (HER2) and basal-like triple-negative breast cancer (TNBC) [4]. The gene discussed is ERBB2; the disease is breast cancer.