Her3 overexpression, which is present in various carcinomas, is related to poor prognosis and is involved in the development of resistance to therapy.[23] One study highlighted the close relationship of Her3 with the development of CRC, and approximately 36% to 90% of patients with CRC have expression of Her3,[24] which is often coexpressed with EGFR and Her2. The gene discussed is ERBB2; the disease is carcinoma.