IL15 and neoplasm: Tumor burden was determined by size, and once there was a palpable tumor, 21 mice were randomly assigned to three treatment groups: (1) vehicle control group (PBS), (2) cryopreserved CD147-IL15-CAR-NK (G-Rex-6W; 5 × 106 cells/mouse), and (3) cryopreserved CD147-IL15-CAR-NK (G-Rex-100M-CS; 5 × 106 cells/mouse).