Interestingly, DUSP22 codes for a protein tyrosine phosphatase that negatively regulates STAT3 and IL-6/STAT3 signaling pathways, indicating DNA methylation-mediated DUSP22 silencing, might be a fundamental effect to activate STAT signaling in RA (Sekine et al., 2006). This evidence concerns the gene STAT3 and rheumatoid arthritis.