KIR2DL1 and glioblastoma: As the findings above still do not unequivocally establish interactions within KIR2DL1 subsets mismatched for cognate HLA ligand as the minimal requirement for NK cell lysis of GBM cells, we hypothesized that culture conditions might further modulate GBM susceptibility to NK cell killing by changing surface expression of inhibitory and stimulatory ligands recognized by NK cells’ NCRs.