ERBB2 and cancer: Activating mutations and genomic amplifications of the tyrosine kinase receptors epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2), and the downstream RAS–mitogen‐activated protein kinase (RAS‐MAPK) pathway, are common in several cancer types, including breast, colorectal, lung cancer, and melanoma, and the clinical benefit of inhibiting this pathway has been thoroughly described [1, 2, 3, 4].