To identify relatively a better HER2-targeted treatment regimen among trastuzumab, pertuzumab, T-DM1, lapatinib in combination with standard treatment (chemotherapy or hormone therapy or endocrine therapy without HER2-targeted drugs) in HER2-positive breast cancer, we performed a comprehensive systematic network meta-analysis of HER2-targeted agents combined with standard treatment for HER2+ breast cancer and evaluated the relative merits of the different regimens. This evidence concerns the gene ERBB2 and breast cancer.