IDO1 and melanoma: As anticipated, expression of a series of interferon-inducible genes [e.g., IRF1, IFI27 (promote cell death, mediate the IFN induced apoptosis), IFI6, IFI35, ISG20], as well as IFN downstream effectors [e.g., IDO1 etc.] were markedly upregulated following IFN-γ treatment of control melanoma cells; this upregulation was significantly attenuated in cells overexpressing LNK [both A375 (Fig. 4b) and M202 (Supplementary Fig. 6)].