In vitro, montelukast demonstrated an inhibitory effect on M5-induced overexpression of factors associated with hyperproliferation (KI67, PCNA), inflammatory cytokines (IL-17A, IL-17F 34, IL-6), angiogenesis (TGF-α 35, VEGF 36, and HIF-1α 37), keratogenesis (KRT16 38, KRT17 39, and cyclin E1 40), and autoimmunity (S100A12 41, S100A15 42, hBD-2 43, and hBD-3 44) in HaCaT keratinocytes. The gene discussed is IL17A; the disease is Autoimmunity.