Additionally, findings from the KATHERINE trial (NCT01772472) indicated that adjuvant treatment with T‐DM1 reduced the risk of recurrence of invasive disease or death by 50% compared with continuing adjuvant trastuzumab among patients with HER2‐positive early breast cancer and residual invasive disease after neoadjuvant chemotherapy plus HER2‐targeted therapy.107. This evidence concerns the gene ERBB2 and breast cancer.