ERBB2 and head and neck squamous cell carcinoma: Initial diagnoses were SCCHN (n = 21 [39%]), ESCC (n = 15 [28%]), HER2-overexpressing breast cancer (n = 10 [19%]), and gastric cancer (n = 8 [15%]); most patients (91%) had ≥ stage IV disease at study entry (Table 1).