Despite improved survival rates for early breast cancer (EBC) patients in the era of a multidisciplinary team approach, optimal locoregional and contemporary systemic treatments, patients with luminal B breast cancer (i.e., hormone receptor positive with high proliferation with or without HER2‐amplification) continue to have higher rates of relapse and poorer EBC‐specific survival when compared with luminal A disease.1, 2. Here, ERBB2 is linked to breast cancer.