We now count at least 20 histological subtypes of invasive breast cancer, defined by morphologic growth patterns and cytological appearance [1] and three broad biological subtypes, based on the expression of diagnostic biomarkers (oestrogen (ER) and progesterone (PR) receptor positive; HER2 positive; and triple negative (lacking hormone receptors and HER2). This evidence concerns the gene ERBB2 and invasive breast carcinoma.