The PHENIX trial reported that the mPFS of patients with HER2-positive advanced breast cancer who failed to trastuzumab treatment in the pyrotinib plus capecitabine group and the placebo plus capecitabine group is 11.1 months and 4.1 months (HR=0.18, 95%CI 0.13-0.26; P<0.001), respectively (18). Here, ERBB2 is linked to breast cancer.