ERBB2 and breast cancer: Trastuzumab 6 mg/kg + pertuzumab 420 mg + docetaxel 75 mg/m2 (TPD) triweekly was started first, as TPD is considered the first choice of treatment for HER2-positive advanced breast cancer [1], and trastuzumab + pertuzumab (TP) has been reported to reach the brain despite the presence of the BBB [5,6].