STAT3 is activated in keratinocytes by a wide range of psoriasis-associated cytokines [e.g., interleukin (IL) 6, IL-22, IL-23 and IL-17] and mediates psoriatic hallmarks such as hyperplasia, increased proliferation and expression of the autoantigen keratin 17 (12). The gene discussed is IL17A; the disease is psoriasis.