GPX4 and rheumatoid arthritis: To determine whether ferroptosis is involved in the pathogenesis of RA, we evaluated the expression of 12 FRGs that were differentially expressed between the RA and HC groups and found that six (ATG5, FTH1, GSS, NCOA4, TFRC and TP53) were upregulated, and six (ACSL1, GPX4, LPCAT3, MAP1LC3B, SLC3A2 and TF) were downregulated in the RA group (Figure 2A).