Given that ovarian tumors express high levels of stem cell factor (KIT ligand) [35], inhibition of the c-KIT/PI3K/Akt/mTOR pathway may reduce IDO expression, and may also limit signaling through CREB, STAT3 and HIF-1α (Figure 1), all of which potentially contribute to immune suppression and disease progression. This evidence concerns the gene IDO1 and ovarian neoplasm.