IBD is under the influence of the expression of various cytokines, their receptors, growth factors, and proteins involved in molecular pathways such as interleukin (IL)-23R, IL-12B, positive regulatory domain I element (PRDM1), Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), signal transducer and activator of transcription 4 (STAT4), and Ikaros family zinc finger protein 1 (IKZF1). This evidence concerns the gene JAK2 and inflammatory bowel disease.