In similar fashion within the confines of the tumour, CTLA-4 fosters immunosuppression through the induction and differentiation of Treg cells along with the upregulation of IL-10 and IDO (indoleamine-2,3-dioxygenase) by means of a CD80 and CD86 counter signaling approach [63,64,65]. The gene discussed is IDO2; the disease is neoplasm.