ERBB2 and neoplasm: In the field of targeted anticancer therapy, where the drug mechanism of action consists in the direct interference with an established oncogenic driver (such as epidermal growth factor (EGF) receptor or human epidermal growth factor receptor 2 (Her2) expression), single analyte biomarkers directly measuring the presence or absence of the drug target on tumour cells have traditionally been used in the clinic to identify the patient subset that would likely benefit from the targeted treatment.