NFATC1, the main cytokine involved in RANKL-induced osteoclastogenesis, was also upregulated in active RA synovial tissues, compared to inactive RA, OA, or normal synovial tissues [33] and our results confirmed that NFATC1 was expressed in synovial tissues, and that its level was higher in RA patients compared to OA patients. Here, NFATC1 is linked to rheumatoid arthritis.