EGFR and rheumatoid arthritis: KEGG pathway enrichment analysis demonstrated that the six hub target-related KEGG pathways included the MAPK signaling pathway, resistance to epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKIs), microRNAs in cancer, the PI3K–Akt signaling pathway, AGE–RAGE signaling pathway in diabetic complications, HIF–1 signaling pathway, endometrial cancer, central carbon metabolism in cancer, IL–17 signaling pathway, rheumatoid arthritis, P53 signaling pathway, platinum drug resistance, etc (Fig. 7).