pCR is associated with improved long-term outcome and the Collaborative Trials in Neoadjuvant Breast Cancer (CTNeoBC) pooled analysis demonstrated that pCR following neoadjuvant chemotherapy combined with trastuzumab was associated with improved long-term outcome in the HER2-positive subgroup irrespective of hormone receptor status (event-free survival (EFS) HR 0.39, (95% CI: 0.31–0.50) and overall survival (HR 0.34, (95% CI: 0.24–0.47) [9]. Here, ERBB2 is linked to breast cancer.