POU5F1 and Alzheimer disease: Fibroblasts provide an exclusive rationale and opportunity where findings from cells can be translated to human subjects; therefore, in the present study, we attempt to investigate the effect of melatonin administration on the expression of the core transcription factors Sox2, Oct4, and Nanog in human skin fibroblasts derived from young, aged, and AD human subjects and affirmed the findings in neuronal cells with significant correlation.