One of the key questions in stem cell and cancer biology is to understand the cellular hierarchy governing tissue development and maintenance and the cancer cell of origin. In a study published in Cell Reports, researchers lead by Cédric Blanpain, MD/PhD, WELBIO investigator and Professor at the Université libre de Bruxelles, Belgium, identified a novel lineage-restricted stem cell in the mammary gland.
The mammary gland is composed two main cellular subtypes: the basal cells and luminal cells. While luminal cells secrete water and nutriments to produce the milk during lactation, the basal cells, through their contraction, guide the circulation of the milk throughout the ductal tree. Luminal cells can be subdivided into estrogen (ER)/progesterone (PR) positive and negative cells.
In this study published in Cell Reports, Alexandra Van Keymeulen and colleagues generated a new transgenic line-allowing lineage tracing of ER+ luminal cells to investigate luminal cell heterogeneity and identify the origin of ER+ luminal cells and the mechanisms regulating their pubertal expansion and adult maintenance.