CD8A and neoplasm: Taken together, these results indicated that the low spontaneous tumor frequency of Klf1K74R/K74R mice in the period of old age was associated with strengthened intrinsic antitumor immunity via increased frequency and tumor infiltration of effector CD8+ T cells and NKT cells that may also contribute to prolonging lifespan in the Klf1K74R/K74R mice.