ARG1 and neoplasm: Other recent studies have proven that the TGF-β1 secreted by CAFs significantly enhanced the level of Ln-γ2, which is encoded by LAMC2 via c-Jun N-terminal kinase signaling in tumor cells to prevent access of T cells to the tumor nest, that Treg cells exerted negative regulatory effects on immune responses caused by the tumor through cell-to-cell contact with various immune cell subsets and by secreting inhibitory cytokines, and that MDSCs can upregulate the activity of Arg-1, thus leaving immune cells in the unresponsive and tolerant state, which mediates the dysfunction of T cells (29–31).