[Vaccine therapies against digestive-system cancers]

Cancer vaccine is a promising tool to achieve therapeutic responses in patients by inducing anti-tumor immunity. Several cancer vaccine trials have been performed in patients with digestive-system cancers. Two major candidates are peptide vaccine and dendritic cell (DC) vaccine. Since their clinical impacts are still limited, extensive studies are underway in order to identify more effective antigens or to potentiate DC functions. We developed a novel DC possessing potent stimulating activity for Th1, CTL, and NK cells, which are desirable for clinical DC vaccines. We performed the clinical trial using such DC for the treatment of colorectal cancer. In some of vaccinated patients, the capacity of NK cells and CTLs was successfully enhanced. Thus, cancer vaccines could be a therapeutic option for digestive-system cancers.