EGFR and gastric cancer: In addition, the cluster related to prognosis, biomarker, immunohistochemistry, lymph node metastasis, and overall survival was positioned in the basic themes field; the cluster related to meta-analysis, polymorphism, P53, gastric cancer, and single nucleotide polymorphism was positioned in the emerging or declining themes field; the cluster related to chemotherapy, cisplatin, immunotherapy, EGFR, and docetaxel was positioned in the niche themes field (Figure 7D).