TLR4 and neoplasm: In the first study, which was conducted by our group, mice were immunized with tumor peptides simply mixed with a free form of an α-GalCer analog, and we observed a slight increase in tumor-specific CD8+ T-cell response and protective immunity, both of which were further enhanced by co-administration of monophosphoryl lipid A (MPLA), a TLR4 agonist (24).