ERBB2 and breast cancer: Targeting driver mutations, such as the EGFR mutation in non‐small cell lung cancer, the KRAS mutation in colorectal cancer, the BRAF mutation in melanoma, the FLT3 mutation in acute myeloid leukemia (AML), human epidermal growth factor receptor 2 (HER2) amplification in breast cancer, has become a key strategy in precision oncology.15