Immunoediting

[1] Immunoediting is characterized by changes in the immunogenicity of tumors due to the anti-tumor response of the immune system, resulting in the emergence of immune-resistant variants.

Cells of the innate immune system recognize the presence of a growing tumor which has undergone stromal remodeling, causing local tissue damage.

In the second phase, newly synthesized IFN-gamma induces tumor death (to a limited amount) as well as promoting the production of chemokines CXCL10, CXCL9 and CXCL11.

These chemokines play an important role in promoting tumor death by blocking the formation of new blood vessels.

Lymphocytes and IFN-gamma exert a selection pressure on tumor cells which are genetically unstable and rapidly mutating.

During this period of Darwinian selection, new tumor cell variants emerge with various mutations that further increase overall resistance to immune attack.

[3] In the escape phase, tumor cells continue to grow and expand in an uncontrolled manner and may eventually lead to malignancies.

During the elimination phase , immune effector cells such as natural killer cells , with the help of dendritic and CD4+ T-cells , are able to recognize and eliminate tumor cells (left). As a result of heterogeneity, however, tumor cells which are less immunogenic are able to escape immunosurveillance (right).