ARG1 and neoplasm: Further, up-regulation of fatty-acid synthase (FASN) by M-CSF in tumor infiltrating myeloid cells was required for PPARβ/δ-dependent expression of immunosuppressive and pro-angiogenic genes (e.g. IL-10, Arg1 and VEGF) and consequent promotion of tumor progression [74], in a model of Lewis lung cancer.