Phenotypically, tumor primed NK cells appear distinct from resting NK cells in that they exhibit reduced expression of activating receptors (e.g., CD16, NKG2D, NKp46), both in terms of intensity and proportion, whereas both the proportion and intensity of expression of co-receptors (e.g., CD69 and CD25) are up-regulated (19, 20). Here, KLRK1 is linked to neoplasm.