HER2 protein membranous overexpression was found in 1.6–11% of patients with primary CRC (Ingold Heppner et al. 2014; Seo et al. 2014; Kavanagh et al. 2009) and 2–9.5% of mCRC patients (Ross et al. 2018; Wang et al. 2020). This evidence concerns the gene ERBB2 and colorectal carcinoma.