STAT1 and rheumatoid arthritis: Second, RA patient CD4+ T cells exhibit hypermethylated genes, including JUN, STAT1, PTEN, and CD44, compared to healthy controls, whereas hypomethylated genes include KRAS and ALB. Additionally, the expression levels of STAT5B, SOCS3, JUN, STAT1, KRAS, ALB, and CD44 were increased in RA.