According to the 12th St Gallen International Breast Cancer Conference, BrCa can be classified into the following five subtypes, which can facilitate the selection of treatment strategies: luminal‐A, luminal‐B [human epidermal growth factor receptor 2 (HER2)‐positive], luminal‐B (HER2‐negative), HER2‐positive, and triple negative (Goldhirsch et al., 2011). Here, ERBB2 is linked to breast cancer.