SCA-1 Labels a Subset of Estrogen-Responsive Bipotential Repopulating Cells within the CD24+ CD49fhi Mammary Stem Cell-Enriched Compartment Academic Article uri icon


  • Estrogen stimulates breast development during puberty and mammary tumors in adulthood through estrogen receptor-α (ERα). These effects are proposed to occur via ERα+ luminal cells and not the mammary stem cells (MaSCs) that are ERαneg. Since ERα+ luminal cells express stem cell antigen-1 (SCA-1), we sought to determine if SCA-1 could define an ERα+ subset of EpCAM+/CD24+/CD49fhi MaSCs. We show that the MaSC population has a distinct SCA-1+ population that is abundant in pre-pubertal mammary glands. The SCA-1+ MaSCs have less stem cell markers and less in vivo repopulating activity than their SCA-1neg counterparts. However, they express ERα and specifically enter the cell cycle at puberty. Using estrogen-deficient aromatase knockouts (ArKO), we showed that the SCA-1+ MaSC could be directly modulated by estrogen supplementation. Thus, SCA-1 enriches for an ERα+, estrogen-sensitive subpopulation within the CD24+/CD49fhi MaSC population that may be responsible for the hormonal sensitivity of the developing mammary gland.


  • Dall, Genevieve
  • Vieusseux, JL
  • Korach, KS
  • Arao, Y
  • Hewitt, SC
  • Hamilton, KJ
  • Dzierzak, E
  • Boon, WC
  • Simpson, ER
  • Ramsay, RG
  • Stein, T
  • Morris, JS
  • Anderson, Robin L
  • Risbridger, GP
  • Britt, KL

publication date

  • 2017