STAT1 and psoriasis: Cytokines such as IFN-γ, IL-17A or IL-22 bind to cell surface receptors and the signal transduction occurs through JAKs, which in turn promotes STAT1 and/or STAT3 phosphorylation and activation in psoriasis (Wolf et al., 2010; Shi et al., 2011; Kim et al., 2014; Zhang et al., 2018; Itoh et al., 2019).