In a study by Shibata-Kobayashi et al., the HER2 positivity rate was 10% among 10 ESCC cases treated with concurrent chemoradiation therapy (CCRT), and the level of HER2 IHC expression was assessed using the immunoreactive scoring (IRS) system [16]. The gene discussed is ERBB2; the disease is esophageal squamous cell carcinoma.