Furthermore, we develop prognostic models with high accuracy to predict the chemotherapeutic response, which are validated by PRM assay in an independent validation cohort composed of 60 GC patients (50% sensitive and 50% non-sensitive patients) receiving either DOS (N = 20), XELOX (N = 20), or anti-HER2 (N = 20) therapies. Here, ERBB2 is linked to gastric cancer.