We next examined tumor-associated macrophages (TAMs) in intestinal polyps by immunohistochemical staining of F4/80, a marker for macrophages, and found that macrophages were more abundantly infiltrated in tumors of Ifngr1−/−ApcMin/+ mice than in those of Ifngr1+/+ApcMin/+ mice (Figure 4B). Here, IFNGR1 is linked to neoplasm.