In this study, patients with HER2-positive primary breast cancer (T1c-3 N0-1 M0; target lesion ≤ 7 cm) were randomized to different lengths of neoadjuvant induction anti-HER2 therapy with lapatinib and trastuzumab followed by weekly paclitaxel plus anti-HER2 therapy, and in estrogen receptor (ER)-positive patients, with or without endocrine therapy; the primary endpoint was comprehensive pCR (CpCR) rate, including residual ductal carcinoma in situ of the breast (ypT0 or Tis). This evidence concerns the gene ERBB2 and ductal breast carcinoma in situ.