Breast cancer (BC) is the most common cancer in women worldwide and even though the 5‐year overall survival (OS) rate reaches 88% in Germany,1 in about 20% of patients,2 in the so‐called triple‐negative breast cancer (TNBC) patients with the absence of the hormonal receptors as well as the growth factor receptor HER2 on the primary tumour, long‐term outcome is poor.3 Here, ERBB2 is linked to breast cancer.