ARG1 and cancer: Finally, we identified different genes involved in both amino acid metabolism, such as ERICH1, GLS, CTSC and ARG1 and amino acid modifying enzymes, such as NAT2, UST and OXR1. To understand the depth of cancer-induced monocyte reprogramming towards MDSCs, we compared suppressive CD14+ cell gene profiles to gene signatures of human bone marrow (BM) derived MDSCs (BM-MDSCs, n = 8 independent donors) obtained by in vitro differentiation of BM cells in presence of a cytokine cocktail composed by G-CSF and GM-CSF, as previously reported [13] (Additional file 1: Figure S5C).