Furthermore, several cytokines such as IFN-γ, interleukin-12 (IL-12), interleukin-22 (IL-22) and IL-23, which are regulated by the Janus Kinase- Signal transducers and activators of transcription (JAK-STAT) signaling pathway, have been identified as having a role in the development of psoriasis (27). This evidence concerns the gene IFNG and psoriasis.