Furthermore, there seemed to be a tumor cell line susceptibility to effector cell killing, with UT-SCC-14-F.luc and UT-SCC-42B-F.luc cell lines being more efficiently killed by primary NK cells as opposed to NK-92 cells, likely as a result of a more favorable match between primary NK cell receptors and tumor target ligands (72). This evidence concerns the gene KLRD1 and neoplasm.