ERBB2 and breast cancer: Currently, one third of clinically lymph node positive (cN+) patients achieve axillary pCR after PST [[3], [4], [5], [6], [7], [8]] with highest rates of up to 80 % in patients with hormone receptor (HR) negative/Human Epidermal growth factor Receptor 2 positive (HER2+) breast cancer [6,9].