As Ido1 is scarcely expressed in murine tumour cells, analysis of the effects of tumoural IDO1 expression is often only possible in mice implanted with human tumour cells, and reconstitution with human allogeneic lymphocytes has been employed for the analysis of the resulting immune effects.122 However, even in mouse cells expressing Ido1, its regulation can differ substantially from that of human IDO1 in the same cell types. Here, IDO1 is linked to neoplasm.