NR4A2 and rheumatoid arthritis: NR4A2 is also highly expressed in inflamed synovial tissues from individuals with RA and psoriatic arthritis as well as in cartilage from individuals with osteoarthritis (OA) (Murphy et al., 2001; McEvoy et al., 2002; Ralph et al., 2005; Mix et al., 2007; Aherne et al., 2009; Ralph et al., 2010; Mix et al., 2012).