IL2 and neoplasm: A study in a xenograft mouse model showed progress with in vivo persistence of NK cells by changing the mode of delivery from IV to IP, but this study required very high starting dose of in vitro IL-2 pre-activated NK cells (20×106), enriched by T and B cell depletions of PBMCs, and high dose IL-2 (75,000 U/day IP daily for 3 weeks) in order to allow reduction in tumor burden with MA-148/GFP-Luc ovarian tumor cells [16].