ERBB2 and breast cancer: Indeed, a pooled analysis of 33 studies published in 2021, comprising 57,351 patients, showed a pCR rate of 60% for HR−/HER+ BC, followed by 59% for HER+ disease, 48% for triple-negative breast cancer (TNBC), 45% for HR+/HER2+, 35% for luminal B disease, 18% for HR+/HER2+, and 13% for luminal A disease.