Currently, several therapies are approved for GC and GEJC, including trastuzumab (a first-line treatment combined with cisplatin-based chemotherapy for HER-2 positive tumors), pembrolizumab (used as first-line therapy for patients with unresectable or metastatic HER2-positive tumors and PD-L1 expression, in combination with trastuzumab, fluoropyrimidine, and platinum-based chemotherapy), and ramucirumab (a second-line therapy administered solo or alongside chemotherapy) (4, 6). Here, ERBB2 is linked to gastric cancer.