Philipp et al. reported that restoring SPI1 levels fully restores the long-term regenerative potential of hematopoietic stem cells (HSCs) and controls the transcription of multiple cell cycle regulatory factors to prevent excessive division and depletion of HSCs.30 SPI1 has been demonstrated to induce proliferation in erythroid progenitors,31,32 but inducible SPI1 overexpression was found to reduce proliferation in HSCs.33 Furthermore, extensive discussions on SPI1 have taken place regarding degenerative diseases such as Alzheimer’s disease. The gene discussed is SPI1; the disease is Alzheimer disease.