Well-established predictive biomarkers include HER2 overexpression which predicts breast cancer response to anti-HER2 therapies like trastuzumab and KRAS, NRAS and BRAF mutations which predict resistance to Epithelial Growth Factor Receptor (EGFR) inhibitors in CRC (Jørgensen et al., 2016). Here, ERBB2 is linked to breast cancer.