Muraoka et al. [9] reported that immunization with a peptide vaccine without an adjuvant increased apoptosis in vaccine-induced CD8+ T cells; in contrast, immunization with a peptide vaccine with a TLR9 stimulant reduced apoptosis in vaccine-induced CD8+ T cells and induced a significant anti-tumor effect in a mouse model. The gene discussed is CD8A; the disease is neoplasm.