ARG1 and neoplasm: Expression of Arginase-1 (Arg-1), Found in inflammatory zone-1 (Fizz-1), chitinase 3-like-3 (Ym- 1), mannose receptor (MRC1/CD206) and Macrophage galactose-type C-type lectins 2 (MGL-2) were increased in B16F10-ARF−/− tumor xenografts, confirming M2 polarization of macrophages (Figure 5A).