Consistently, we detected significantly higher IFN-γ level of mice serum in MSCs-Sirt1 treatment group than those in other different treatment groups and the antitumor effect of MSCs-Sirt1 in tumor-bearing mice was greatly impaired when neutralization of IFN-γ was performed, which suggested that IFN-γ showed an important effect on MSCs-Sirt1-induced tumor inhibition in tumor-bearing mice. The gene discussed is SIRT1; the disease is neoplasm.