WD repeat- and FYVE domain-containing protein 4 (WDFY4) is highly expressed in lymph nodes and the spleen; previous studies have shown that aberrations in this gene are associated with autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis.22,23 However, the significance of WDFY4 in cancer is yet to be explored. Here, WDFY4 is linked to rheumatoid arthritis.