ARG1 and neoplasm: Immunohistochemical analysis revealed a significant increase in intratumoural infiltration of M1-like macrophages (iNOS+) at the expense of M2-like macrophages (Arg1/CD68+), and an increase in CD8 + T cells in Mettl1 +/- and Mettl1flox/flox tumours compared to Mettl1+/+ tumours (Fig. 7G; Supplementary Fig. S9E, S9G).