RESEARCH a r

Full list of author information is available at the end of the articleBackground The role of tumor necrosis factor (TNF) in inflammatory diseases such as rheumatoid arthritis (RA), juvenile idiopathic arthritis (JIA), and psoriasis is well established, as is the benefit of TNF inhibition in the treatment of these disorders [1]. TNF is key to natural killer cell-mediated destruction of tumor cells in mice [2]. The role of TNF in human cancer biology is less clear and it has been hypothesized that TNF inhibition may increase the risk of malignancies [3], particularly with prolonged, continuous exposure to TNF blockade [4]. An increased risk of skin cancers, including nonmelanoma skin cancer and melanoma, has been reported with the use of TNF blockers [5-7]. Adult patients with rheumatic diseases, especially those with severe disease, appear to have an inherently greater * Correspondence