We found increased expression of Arginase 1 (Arg1) in monocytes and macrophages in mice injected with ENPP1WT-OE 4T1 cells (Fig. 2A and SI Appendix, Fig. S2D), which is associated with pro-tumor myeloid-derived suppressor cells (MDSCs) (34) and M2-like macrophages (35), respectively. Here, ARG1 is linked to neoplasm.