ERBB2 and breast cancer: Neoadjuvant HER2-based therapy is typically used in locally advanced BC (Stage IIb with T3 disease or Stage III) or in patients with an earlier stage HER2+ disease who desire breast-conserving therapy, those who have limited axillary nodal involvement (N1) (which may convert to node-negative disease and thus resulting in sentinel lymph node biopsy), or those whose surgery has been postponed (due to a variety of reasons).