IDO1 and neoplasm: In conclusion it may be suggested that IFN-γ contributes to HPD onset in predisposed patients via the induction of the inflammasome pathway and consequent MDSC recruitment, the induction of IDO1 activity, which may result in the downregulation of p53 in tumor cells, and the activation of AICD, which leads to T-cell depletion (Figure 2).