IL21 and neoplasm: The tumor weight averaged 0.207, 0.522, 0.873, 0.843, 1.439, and 1.591 g for IRES/combination, IRES/GM-SCF-IL-21, IRES/GM-SCF, IRES/IL-21, IRES/GFP, and the control group, respectively, which were significantly different (P < 0.01).