In the in vitro cell model of TNF-α/IFN-γ-induced AD in HaCaT cells, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was performed first to rule out the possibility that the inhibitory efficacy of WIF was due to WIF toxicity in human keratinocyte (HaCaT) cells. This evidence concerns the gene TNF and Alzheimer disease.