Abstract:
Primary liver cancer (PLC) is the first leading cause of immature cancer death in China. Hepatocellular carcinoma (HCC) in China accounts for 93.0% of PLC. Chronic infection with hepatitis B virus (HBV) HCC contributes to 84.4% of HCC. During HBV-induced hepatocarcinogenesis, non-resolving inflammation facilitates viral and host genome mutations via the up-regulated expression of activation-induced cytidine deaminase/APOBEC3s and decreases mutation repair via the down-regulated expression of uracil DNA glycosylase by proinflammatory cytokines such as interleukin-6. The proinflammatory tumor microenvironment (TME) provides necessary conditions for the "mutation-selection-adaptation" evolutionary process of HBV and human hepatocytes and facilitates the retrodifferentiation of mutated hepatic cells. This evolutionary process has two prerequisites: driving somatic mutations and immune-suppressive TME. Cancer-promoting chromosome instability and viral mutations inhibit type I interferon signaling via activating the cyclic GMP-AMP synthase stimulator of interferon genes, induce immune-suppressive inflammation, and recruit immune-suppressive immune cells, including tumor-associated macrophages, regulatory T cells, and myeloid-derived suppressor cells, to build immunosuppressive TME. In the TME, the rapid growth of tumor cell-caused hypoxia activates kynurenine metabolism in the HCC tissues by inducing the expression of immune-suppressive inflammatory factors to promote the expression of PD-1 on regulatory T cells for enhanced immunosuppression; it also inhibits the cytotoxicities of CD8+T and natural killer cells and facilitates angiogenesis. The theoretical update of "Cancer Evo-Dev" highlights the direction of cancer prophylaxis and treatment. The treatments targeting angiogenesis significantly inhibit the growth of HCC, increase anti-tumoral immunity, and enhance the efficacy of immunotherapy. The combination of targeted therapy and immunotherapy should be the major therapeutic option for the treatment of advanced liver cancer.