The development and commercialization of multigene expression‐based assays (eg, Oncotype DX, MammaPrint, Prosigna, etc.)have resulted in a paradigm shift in BC treatment, specifically in the care of estrogen receptor (ER) and progesterone receptor (PR) positive and HER2‐negative early stage BC.37, 38, 39, 40. This evidence concerns the gene ERBB2 and breast cancer.