This important study suggests that neoadjuvant chemotherapy treatment with trastuzumab alone or with pertozumab is the standard of care for patients with primary newly diagnosed HER2-positive breast cancer; patients not achieving a pathological complete response with this regimen, are treated with trastuzumab-emtansine, offering a better opportunity for improving long-term outcome [95]. This evidence concerns the gene ERBB2 and breast cancer.