Several ligands for the activating immunoreceptor NKG2D (natural killer group 2D) (NKG2DL) including the UL16-binding protein (ULBP) family and MHC class I-related chain (MIC) proteins have been described to be selectively overexpressed in human cancer cells like acute myeloid leukemia, lung cancer, ovarian and breast cancer and sarcomas (15). Here, KLRK1 is linked to lung cancer.