Emergence of immunotherapy as a novel way to treat hepatocellular carcinoma

Figure 2 Cellular mechanisms underlying immunoediting. At the elimination phase, newly-appearing cancer cells can be recognized and killed by a number of immune cells, particularly natural killer (NK) cells, and CD8⁺ and CD4⁺ T cells. At the equilibrium phase, variant cancer cells arise that are less immunogenic, and consequently more resistant to being killed by immune cells. Over time, a variety of different cancer variants develop. At the escape phase, one variant may finally escape the killing mechanism or recruit immunosuppressive cells such as Tregs and MDSCs, and eventually form an appreciable tumor mass. MDSC: Myeloid-derived suppressive cell.