Interestingly, in the KrasG12D mouse model of lung cancer, ARG1 inhibition reduces tumor growth and increases T-cell homing and function in tumors.19 Besides ARG1 expression, the release of prostaglandin-E2 (PGE2) by neutrophils and TANs represents another important mechanism of T-cell suppression. This evidence concerns the gene ARG1 and neoplasm.