Our data indicate that in the presence of tumor-derived factors, more CD206+ MHC II− and less CD206− MHC II+ BMDM are generated in vitro from bone marrow progenitor cells but deletion of Camkk2 in myeloid cells attenuates this process, leading to the generation of more M1-like and less M2-like macrophages compared with WT myeloid cells. Here, MRC1 is linked to neoplasm.