IFNG and leukemia: After 96-h exposure of PBMCs to hypoxia (1.5 or 0.5% pO2 ex vivo), we measured CD107a degranulation and IFN-γ production by NK cells against three different tumor targets—a human leukemia cell line K562, a human lymphoblastoid cell line CEM, and a human melanoma cell line A375—using fluorescence-activated cell sorting (FACS).