dsDNA is a powerful activator of the innate immune system4 and acts via several so called pattern-recognition receptors such as TLR-9 (toll-like receptor 9), AIM2 (absent in melanoma 2), DAI (DNA-dependent activator of IRFs), RIG-I (after transformation of DNA by RNA polymerase III)4, 5, and most recently Interferon-γ-inducible protein16 (IFI16) and cGAMP synthase (cGAS) have been discovered and shown to recognize intracellular dsDNA6. The gene discussed is TLR9; the disease is melanoma.