The “loss of self” mediated by the downregulation of MHC molecules as a mechanism of tumor escape hinders the recognition of cancer cells by CD8+ T cells but unleashes the activity of NK cells, which are regulated by the interplay of activating and inhibitory receptors such as KIRs and natural killer group 2D (NKG2D) (83, 84). The gene discussed is CD8A; the disease is neoplasm.