ERBB2 and metastatic melanoma: Major therapeutic successes have been obtained with inhibitors that specifically target constitutively active tyrosine kinases, such as specific inhibitors of the constitutively active form of the BRAF kinase (BRAF‐V600) in BRAF‐V600 mutated metastatic melanoma (Chapman et al., 2011) The use of blocking antibodies specific for an oncogenic pathway has also resulted in therapeutic success (anti‐EGFR antibody in metastatic colon cancer and anti‐HER2 in breast cancer with HER‐2 amplification) (Li et al., 2017; Ross et al., 2009).