The mammary gland undergoes significant remodeling during pregnancy and lactation,
which is fuelled by controlled mammary stem cell (MaSC) proliferation. The scarcity of
human lactating breast tissue specimens and the low numbers and quiescent state of
MaSCs in the resting breast have hindered understanding of both normal MaSC dynamics
and the molecular determinants that drive their aberrant self-renewal in breast cancer. Here,
we demonstrate that human breastmilk contains stem cells (hBSCs) with multilineage …

The breast undergoes extensive remodelling at each pregnancy/lactation, based on
mammary stem cell (MaSC) expansion and differentiation. Most of our knowledge on MaSCs
comes from the resting breast, where these cells are quiescent and in low numbers. In our
laboratory we examine the lactating breast that contains higher numbers of MaSCs, which
we access non‐invasively via breastmilk. Here, we describe the presence of MaSCs
(CD49f+/CD29+) in breastmilk, which were able to self‐renew and differentiate into …