IL21 and neoplasm: For instance, systemic injection of IL-21-producing UCB-MSCs in A2780 ovarian cancer-bearing mice models boosted IFN-γ-generating splenocyte numbers and NK cell cytotoxicity in transplanted models (Hu et al., 2011); on the other hand, intervention suppressed tumor development and enhanced the survival rate of tumor-bearing mice (Hu et al., 2011).