ERBB2 gene mutation mainly happens in ERBB2high cancers, such as cervical squamous cell carcinoma, stomach adenocarcinoma, breast invasive ductal carcinoma, uterine corpus endometrioid carcinoma, cholangiocarcinoma, and bladder urothelial carcinoma (Figure 2A). The gene discussed is ERBB2; the disease is invasive ductal breast carcinoma.