Immunediting

Immunoediting is a concept in cancer immunology describing how the immune system and developing tumors interact to shape tumor immunogenicity. It proposes that cancer evolves under immune pressure through three phases—elimination, equilibrium, and escape—so the immune system can both suppress tumor growth and select for variants that resist attack. The term and framework were introduced in 2002 by Dunn, Old, and Schreiber.

In the elimination phase, innate and adaptive immune components recognize and destroy nascent tumor cells. Cytotoxic T cells and natural killer cells target cancer cells presenting tumor antigens, often neoantigens derived from mutations. Interferon signaling and antigen presentation via MHC class I facilitate recognition, and successful elimination prevents tumor outgrowth.

The equilibrium phase is a dormancy-like state in which surviving tumor cells persist under persistent immune pressure. Tumor cells may acquire mutations or epigenetic changes that reduce their visibility, downregulate antigen presentation, or resist apoptosis. The immune system keeps these cells in check without fully eradicating them, allowing time for further evolution.

During escape, tumor cells acquire mechanisms to avoid detection or destruction. They may lose or alter antigen presentation, upregulate inhibitory molecules such as PD-L1, secrete immunosuppressive factors, and recruit regulatory T cells or myeloid-derived suppressor cells. These changes create an immunosuppressive microenvironment that enables progressive tumor growth.

Clinical relevance lies in understanding why tumors respond differently to immunotherapies and how resistance can emerge. Immunoediting informs strategies to sustain antigen presentation, combine modalities, and anticipate immune escape, shaping approaches to vaccines, checkpoint inhibitors, and other cancer treatments.