ARG1 and neoplasm: Furthermore, in the AOM-treated group, the expression of markers for M2 macrophages (Arg1 and Ym1) and regulatory T cells (Foxp3), which facilitate tumor growth by counteracting anti-tumor immunity46,47, was lower in Pla2g3−/− colon than in Pla2g3+/+ colon, although that of the angiogenic marker Vegfa was comparable between the genotypes (Fig. 2g).