To avoid the non-specific activity of these inhibitors on the tumor cells, we used M2-polarized BMDM from mice with macrophage-specific deletion of Arg1. The Arg1fl/fl; LysMcre (LCArg) mice lack Arg1 expression in macrophages and neutrophils, while the Arg1fl/fl; Tie2cre (TCArg) mice lack Arg1 in all hematopoietic lineage cells [34]. This evidence concerns the gene ARG1 and neoplasm.