XIAP and rheumatoid arthritis: In patients with rheumatoid arthritis, curcumin is able to up regulate pro-apoptotic Bax, and down regulate anti-apoptotic B-cell lymphoma 2 (Bcl-2) and X-linked inhibitor of apoptosis protein (XIAP), inducing apoptosis and, therefore, inhibit the growth of synovial fibroblasts [90].