IDO1 and melanoma: The role of the inhibition of IDO in the antitumor mechanism of the bioavailable analog of brassinin (5-bromobrassinin (Figure 1)) was confirmed in vivo, where this compound suppressed growth of B16-F10 melanoma xenografts in C57BL/6 mice but not in athymic NCr-nu/nu and IDO knock-out mice (Table 1) [28].