These tumours generally lack ER and HER2 expression and are molecularly characterised by the expression of genes associated with both basal epithelium and myoepithelium of the normal mammary gland (e.g. KRT5/6, KRT14, VIM, CDH3, CRYAB, CAV1 and CAV2, as well as EGFR) [2,5]. Here, ESR1 is linked to neoplasm.