In clinical practice, pCR only occurs in a minority of patients, and pCR rates vary according to molecular subtypes; 50–60% of patients achieve pCR in HER2-positive breast cancer (Gianni et al., 2012), while only 5–20% achieve pCR in high-grade luminal cancer (Cortazar et al., 2014; Sikov et al., 2015). Here, ERBB2 is linked to breast cancer.