Interleukin 23 receptor (IL23R), a heterodimer of the IL12 receptor β 1 (IL12R β 1) and IL12R β 2, is a type Icytokine receptor for IL23. IL23R is comprised of two subunits, the IL12R β 1 subunit, which is shared withseveral cytokines, and a subunit that is unique to IL-23. IL23, after binding to IL23R, activates memory T cellsand mediates pro-inflammatory activities in part by the production of IL17 through activation of TH17lymphocytes. IL23R is expressed on T cells, NK cells, dendritic cells, and macrophages. In fact, polymorphismsof the IL23R gene were reported to be associated with susceptibility to inflammatory diseases andautoimmune diseases such as psoriasis, multiple sclerosis, Graves's ophtalmopathy and inflammatory boweldiseases. The IL23R is known to be critically involved in the carcinogenesis of different malignant tumor.