Exposure to acute ultraviolet (UV) irradiation or treatment with the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate (TPA), increases the activation of PTKs including the epidermal growth factor receptor (EGFR) and the downstream STAT3 signaling pathway15, 16, 17, 18, 19, 20. The gene discussed is STAT3; the disease is neoplasm.