ZAP70 and rheumatoid arthritis: We identified three hub genes that interact with drugs in cluster 1, namely, CXCR4, EGFR, and LAMA2, and five hub genes that interact with drugs in cluster 2, namely, GZMB, IL2RB, IL2RG, LCK, and ZAP70. CXCR4 is aberrantly expressed in multiple immune cell populations in RA and has multiple functions, including promoting FLS proliferation, facilitating T cell migration, promoting the differentiation of inflammatory macrophages, and promoting inflammation, angiogenesis, and bone destruction processes (Zhao et al., 2022a).