The conclusion was that single-dose monotherapy with trastuzumab for patients with HER2-positive DCIS does not result in significant clinical, histologic, proliferative, or apoptotic changes, but results in antibody-dependent cell-mediated cytotoxicity (ADCC)-mediated response through natural killer (NK) cells, and may also induce humoral immunity in a T-cell-dependent manner. Here, ERBB2 is linked to ductal breast carcinoma in situ.