FURIN and autoimmune disease: 11 In addition, aberrant FURIN gene expression or enzyme function is associated with human malignancies, such as lung and skin cancers,9,12 and autoimmune diseases, including Sjögren's syndrome and rheumatoid arthritis.13,14 In fact, Vigil RNA interference therapy, which inhibits FURIN expression using a short hairpin RNA (shRNA) construct, is currently in clinical trials as a regimen for several cancers.15 The progression of these cancers is associated with increased concentration of active TGF-β, that is mainly activated by furin-mediated proteolysis.