ERBB2 and breast cancer: A pCR rate of 30.9% was observed in patients with HER2-positive hormone receptor-positive BC treated with an anti-HER2 agent, as compared with 18.3% treated with chemotherapy alone (HR 0.58; 95% CI 0.42–0.829), and the pCR rate was 50.3% in patients with hormone receptor negative HER2-positive BC treated with an anti-HER2 agent versus 30.2% without a neoadjuvant anti-HER2 agent (HR 0.25; 95% CI 0.18–0.34) (13).