ITGAM and neoplasm: This activation further regulates the expansion of MDSCs marked by CD11b + /Gr1+ and the infiltration of macrophages (CD11b + /F480 + ) in distant organs like the lungs, ultimately fostering an inflammatory immunosuppressive microenvironment at pre-metastatic sites.185 It is well-established that IL-1β is primarily produced by tumor-associated granulocytes and macrophages.