Pharmacological inhibition of Arginase-1 has been shown to increase tumor immune cell infiltration and reduce tumor growth in syngeneic mouse models (Rodriguez et al., 2004, Steggerda et al., 2017, Czystowska-Kuzmicz et al., 2019, Narita et al., 2013, Miret et al., 2019). This evidence concerns the gene ARG1 and neoplasm.