Fig. 1.

The mechanisms elaborate to MDSC-mediated immunosuppression in Liver cancer. In the TME, GM-CSF and G-CSF released by tumor cells accumulate and recruit MDSCs. MDSCs suppressed the response and proliferation of T and NK cells via TGF-β, Arg-1 or ROS. MDSCs derived IL-10 and TGF-β accelerate accumulation and immunosuppression of Treg. Similarly, MDSCs derived IL-10 inhibit DC function as well. IL1-α promotes MDSCs recruitment and immunosuppression and suppresses T cells function. Tumor-derived CCL20, IL-17 and IL-6 promote Treg expand and immunosuppression. NK cells can lyse tumor cells by direct contact and release of perforin and granzyme B. Treg cells deprivate for IL-2 to T cells and NKP30 on MDSCs binds to receptors on NK cells to suppress NK function. These constitute the immune microenvironment of liver cancer