ARG1 and neoplasm: Notably, DMXAA not only suppressed tumor cell-induced up-regulation of genes associated with pro-tumorigenic M2 polarization, including Arg1, Csf1r, Il1b and Mrc1, but also strongly stimulated the expression of genes associated with an anti-tumorigenic M1 signature (e.g., Ccl5, Cxcl10, Cd40, Cd86, Il18 and Nos2) (Fig. 4a).