Many cancer biomarkers have been elucidated, such as KRAS in colorectal cancer (Dienstmann et al., 2015), human epidermal factor receptor 2(HER2) in breast cancer (Harbeck and Gnant, 2017), and EGFR in lung cancer (Paez et al., 2004). The gene discussed is ERBB2; the disease is colorectal cancer.