TLR2 recognizes products of epidermal microorganisms, such as Staphylococcus epidermidis and Propionibacterium acnes, to promote inflammation through an increase in LL37, tumor necrosis factor-α, IL-1β, and other inflammatory factors, which in turn induces rosacea-related vasodilation, hyperplasia, and inflammation rash. The gene discussed is TLR2; the disease is rosacea.