We hope that more and more randomized trials, consisting of more than one HER2-targeted agent in combination with chemotherapy/hormone therapy in HER2-positive breast cancer such as the comparable randomized trials that T-DM1+/- pertuzumab versus standard treatment with or without T-MD1+/- pertuzumab, can be increased to represent various and efficacious treatment regimens. This evidence concerns the gene ERBB2 and breast cancer.