New insights into cancer immunoediting and its three component phases—elimination, equilibrium and escape

Deepak Mittal, Matthew M Gubin, Robert D Schreiber, Mark J Smyth

The principles of cancer immunoediting have set the foundations for understanding the dual host-protective and tumour sculpting actions of immunity on cancer and establishing the basis for novel individualized cancer immunotherapies. During cancer immunoediting, the host immune system shapes tumour fate in three phases through the activation of innate and adaptive immune mechanisms. In the first phase, Elimination, transformed cells are destroyed by a competent immune system. Sporadic tumour cells that manage to survive immune destruction may then enter an Equilibrium phase where editing occurs. The Escape phase represents the third and final phase of the process, where immunologically sculpted tumours begin to grow progressively, become clinically apparent and establish an immunosuppressive tumour microenvironment. This review focuses on important recent developments that have enhanced our understanding of each phase of the cancer immunoediting process, summarizes the discovery of new predictive and prognostic biomarkers and discusses development of novel and objectively effective cancer immunotherapies.