CD8A and cancer: The selection of tumor variants resistant to tumor effectors, which is referred as immunoediting, is characterised by three phases, known as the ‘three Es of cancer immunoediting’; Elimination’, which is supported by CD8+ and NK cells; ‘Equilibrium’, involving Th1 cells, IL-12 and IFN-g, and finally; ‘Evasion’ [25,37,38].