In contrast to gastric and breast cancers, the diagnostic criteria for HER2 positivity in CRC have not been fully standardized and have varied across studies (Kapitanovic et al. 1997; Richman et al. 2016; McKay et al. 2002; Park et al. 2018; Conradi et al. 2013). The gene discussed is ERBB2; the disease is breast cancer.