Preclinical studies performed in vitro and in mouse models with orthotopic NB have demonstrated that integration of IL-15 [158] and IL-21 [159] in a NB immunotherapy regimen (with anti-GD2 and GM-CSF) exhibits anti-tumor activity and outperforms the anti-GD2-IL-2 combination [159]. The gene discussed is IL21; the disease is neuroblastoma.