Attenuated Salmonella strains are safe, invasive and tumor-targeting vectors for antitumor gene delivery (15), and the use of attenuated Salmonella strains carrying interleukin (IL)-2 (16), Fas ligand (FasL), IL-18 (17) and fms-like tyrosine kinase 3 (FLT3) ligand (18) led to great progress in antitumor research. Here, FLT3 is linked to neoplasm.