This relatively low proportion of tumour cells and the often weak staining make GATA3 less reliable in the context of CK5-expressing TNBCs, even though it seemed to be the best marker among GATA3, MGB, GCDFP-15 and NYBR1, the latter of which only labelled 6% of the CK5+ TNBC cases with only 3% showing > 5% staining [17], in keeping with a previous report correlating its expression to ER positivity and inversely correlating it to EGFR [18]. The gene discussed is KRT5; the disease is neoplasm.