Nakano et al., found 1859 DMPs between RA and OA patients with hypomethylation of CpG sites located on key genes in RA pathogenesis including CASP1—encodes Caspase 1 that induces cell apoptosis, MAP3K5 a MAP kinase involved in the innate immune system, STAT3 a transcription activator, activated in response to cytokine signalling, MEFV (pyrin) that generates inflammation in response to interferon-gamma signalling. The gene discussed is STAT3; the disease is rheumatoid arthritis.