Adult Mammary Stem Cells: Identity, Location, and Functional Assays

Abstract

The mammary gland is an apocrine organ that undergoes multiple periods of robust change marked with proliferation, differentiation and apoptosis. The profound regenerative potential observed in the mammary gland implies the presence of a population of mammary stem cells (MaSCs) with the capacity to both self-renew and give rise to all mammary lineages. Furthermore, a single mammary epithelial cell enriched for specific cell surface markers has been shown to reconstitute an entire, functional mammary gland in vivo, thereby demonstrating multipotent stem cell potential. The purpose of this chapter is to briefly outline the current state of knowledge on the identity and location of the MaSC, as well as provide a critical overview of the assays utilized to examine MaSC potential.