ERBB2 and breast cancer: In the phase III KATHERINE trial, patients with stage I to stage III HER2-positive breast cancer and residual invasive disease in the breast or axilla following neoadjuvant chemotherapy and HER2-targeted therapy were included; invasive DFS survival was significantly higher in the T-DM1 group than in the trastuzumab group, and the risk of distant recurrence was lower in those who received treatment (von Minckwitz et al., 2019).