Furthermore, it was discovered that TLR ligands, particularly polyIC (a synthetic double-stranded RNA polyinosinic polycytidylic acid), stimulated an increased capacity of hepatocellular carcinoma cell line (CCL-9.1) in mice to release Hepatoma Derived Growth Factor (HDGF), as well as Foxp3+ Treg cells to proliferate, which together inhibit the release of perforin and granzyme B from effector CD8+ T cells into the tumor microenvironment for the purpose of assisting cancer cell immune escape (35). Here, HDGF is linked to hepatocellular carcinoma.