Since hUCMSCs have attracted much attention due to their availability, low immunogenicity, as well as strong tropism for tumors in contrast to hMSCs from other sources[8-10], we particularly focused on the investigation using hUCMSCs to express IL-21 via lentiviral vector to assess the therapeutic effect of hUCMSCs- LV-IL-21 on SKOV3 ovarian cancer xenograft-bearing mouse model in the current study. This evidence concerns the gene IL21 and ovarian carcinoma.