Earlier studies reported that NK cells can kill autologous and allogeneic tumor cells without involving the MHC.(32) Lymphomas deficient in MHC antigens were rejected in vivo in contrast to MHC-expressing lymphomas.(33) Such loss of MHC expression failed to activate inhibitory NKG2 receptors (other than the activating NKG2D). Here, KLRK1 is linked to neoplasm.