By binding to HER-2, Trastuzumab inhibits tumor metastasis and proliferation, and strengthens immune function.2,6 Pyrotinib is a novel irreversible tyrosine kinase inhibitor that inhibits HER-1, HER-2, and HER-4, and reduces the formation of HER family homo/heterodimers.7–9 The aim of this study was to determine the effect of Pyrotinib combined with Trastuzumab in HER-2 positive BC to provide a reference basis for the treatment of HER-2 positive BC. Here, ERBB4 is linked to breast cancer.