ARG1 and neoplasm: Compared with C-MOs, MAMPCs expressed higher levels of TAM signature genes (i.e., Arg1, Cdh1, Hmox1, Il1r2, Mrc1, and Stab1) that were also highly expressed by MAMs, suggesting that differentiation of C-MOs to MAMPCs (M-MDSCs) is directed toward the tumor-promoting macrophages.