Based on this assumption, it is not surprising that IDO1 is not induced by Tα1 at the tumor site, considering that B16 cells, although not expressing IDO1 (Holmgaard et al, 2015), are potent inducers of IDO1 in other cell types (Sharma et al, 2007; Holmgaard et al, 2013). The gene discussed is IDO1; the disease is neoplasm.