EGFR and rheumatoid arthritis: Next, we constructed a PPI network for DEGs using the STRING database, and the top ten hub genes that were further analyzed by Cytoscape software as follows: PTPRC, LCK, CDC20, JUN, CDK1, KIF11, EGFR, VEGFA, MAD2L1, and STAT1. The statistical results validated by the qRT-PCR and Western blot system show that the expression levels of VEGFA and EGFR were significantly increased in RA samples.