The subsequent phase III JACOB trial in 2018 demonstrated that the addition of pertuzumab (840 mg every three weeks) to trastuzumab and chemotherapy as first-line treatment for HER2-positive metastatic GC or GEJA tended to increase OS compared with standard treatment (17.5 vs 14.2 months, HR = 0.84, P = 0.057) (Kang et al. 2014a; Tabernero et al. 2018; Huang et al. 2022d). Here, ERBB2 is linked to gastric cancer.