IDO1 and neoplasm: These included genes coding for CD274/PD-L1, IDO1 (indoleamine-2,3 dioxygenase 1) which contributes to tumor immunosuppression by enzymatically degrading tryptophan [29], CXCL13, CIITA, TGM2 (transglutaminase 2) which is an important enzyme and autoantigen in CeD [30], the vitamin D receptor and CYP27B1, an enzyme which catalyzes the production of vitamin D3, a factor promoting innate immunity and modulating adaptative immunity [31, 32].