Expression profile of the human IDO1 protein, a cancer drug target involved in tumoral immune resistance

Tryptophan catabolism by indoleamine 2,3-dioxygenase (IDO1) is a physiological immunoregulatory mechanism often hijacked by tumors. Our recent extensive study of IDO1 protein expression in human tissues showed expression in mature dendritic cells and in pulmonary and placental endothelial cells. IDO1 was also expressed in 56% of tumors, either by tumoral, stromal, or endothelial cells. These results and reagent will guide the clinical development of IDO1 inhibitors for cancer therapy.