IDO1 and neoplasm: This suggests that inhibiting AhR could enhance the prognosis of pancreatic cancer and tumors that are present in their original location.68 The presence of L. murinus in mice was found to result in larger tumors compared to germ-free (GF) mice, and TAMs showed increased expression of pro-tumor genes such as ARG1, indoleamine 2,3-Dioxygenase 1 (Ido1), and IL-10.