Methods to classify different clinicopathologic types of breast cancers range from evaluation of the immunohistochemical (IHC) staining of hormonal and protein biomarkers (Estrogen receptor ER, Progesterone receptor PR and Epidermal Growth Factor Receptor HER2/neu), etc., to molecular profiling and intrinsic subtyping based on RNA expression [1–3] and integrated transcriptomics with copy number aberrations (IntClust) [4–7] in bulk populations of cancer cells. The gene discussed is ERBB2; the disease is cancer.