A Phase II Trial of HKI‐272 (Neratinib), Neratinib, and Capecitabine, and Ado‐Trastuzumab Emtansine for Patients With Human Epidermal Growth Factor Receptor 2 (HER2)‐Positive Breast Cancer and Brain Metastases. This evidence concerns the gene ERBB2 and breast cancer.