ERBB2 and breast carcinoma: Pooled analysis of 33 studies, including 57,531 patients, has demonstrated that axillary pathological complete response (pCR) rates following neoadjuvant chemotherapy with clinically positive axillary nodes vary widely within breast cancer subtypes, with hormone receptor-/HER2+ cancers showing the highest rate (60%) while only 13% of patients with luminal A subtype tumors achieved pCR.