Fig. 2
From: Hepatic stellate cells: central modulators of hepatic carcinogenesis
Immunomodulatory effects of HSC in HCC. Intratumoural HSC (iHSC) promote HCC progression through i) an increase in Treg cell induction and immunosuppressive function and ii) upregulation of B7-H1 on iHSC resulting in increased ligation of its receptor (PD-1) on activated T-cells, leading to increased apoptosis of activated T cells with subsequent inhibition of T-cell-mediated tumour cell apoptosis. This results in HCC immunotolerance and a permissive environment for tumour growth. PD-1, programmed death ligand; B7-H1 human B7 homolog 1; ECM, extracellular matrix