With hormone receptor immunohistochemistry (IHC) stains of less than 1% for oestrogen and progesterone2 and the absence of HER2 protein overexpression orHER2 gene amplification (or both)3, TNBC accounts for 12 to 17% of all breast cancers, typically affects younger women and typically carries a poor prognosis4. Here, ERBB2 is linked to breast cancer.