Because homozygous Spi1-knockdown mice also become moribund from T-cell lymphoma and acute myeloid leukemia starting at 3 months of age10, we utilized only Spi1 heterozygous knockdown (Spi1+/−;APP/PS1) mice and wild-type for Spi1 (Spi1+/+;APP/PS1) mice. The gene discussed is PSEN1; the disease is acute myeloid leukemia.