Talabostat (Val-boroPro; PT100) can stimulate immune responses against tumors involving both the innate and adaptive branches of the immune system.In WEHI 164 fibrosarcoma and EL4 and A20/2J lymphoma models, Talabostat (Val-boroPro) causes regression and rejection of tumors. The antitumor effect appears to involve tumor-specific CTL and protective immunological memory.Talabostat (Val-boroPro) treatment of WEHI 164-inoculated mice increases mRNA expression of cytokines and chemokines known to promote T-cell priming and chemoattraction of T cells and innate effector cells[4].