To the best of our knowledge, these observations represent the first demonstration of a modifiable host-level oncodriver (HER2/neu)-specific immune disparity that is associated with pathologic response to neoadjuvant T + C. These findings may have important implications for immune monitoring and/or design of adjunctive immune therapies to improve outcomes in trastuzumab-treated HER2pos BC patients. This evidence concerns the gene ERBB2 and breast cancer.