ARG1 and neoplasm: Importantly, in vitro antibody-mediated neutralisation of ILC2-derived IL-4 and IL-13 reduced tumour MDSC Arg1 levels, and similarly genetic deletion of IL-13 in mice with CRC decreased Arg1+ MDSCs, increased IFNγ production by Th1 cells and CD8+ T cells, and significantly reduced tumour burden [28].