ERBB2 and breast cancer: This is in line with previous studies showing higher pCR after NACT in aggressive breast cancer subtypes, such as ERBB2+ and TNBC.23,24 Similar to our study, the rate of pCR was higher for TNBC (68%) and lower for HR+ (17.4%) in the I-SPY2 trial.25 Molecular biology assessment of patients can identify those who may have excellent responses to NACT.