Mature DCs can first secret IL-1β, IL-2, IL-6, TNF-α, and IFN-γ to promote the differentiation of T cells into CD8+ subset and then activate those CD8+ T cells to CTLs through the cross-presentation of tumor antigen peptides with major histocompatibility complex class I (MHC I). The gene discussed is CD8A; the disease is neoplasm.