For instance, the ATTRACTION - 4 trial demonstrated that the addition of nivolumab to chemotherapy significantly improved progression-free survival (PFS) compared to chemotherapy alone in Asian patients with untreated, HER2-negative, unresectable advanced or recurrent gastric and gastroesophageal junction adenocarcinoma (hazard ratio [HR] 0.68 (11). Here, ERBB2 is linked to gastroesophageal junction adenocarcinoma.