Between the high number of breast cancer patients and the pink ribbons seen all over, breast health is and will always be a hot topic. The breast is a fascinating system of different cell and tissue types, and today’s image is from a paper looking at a population of epithelial cells in the breast.
Breast tissue contains two layers of epithelial sheets—an outer layer of myoepithelial cells (MECS) and an inner layer of luminal epithelial cells (LECs). The LECs greatly expand during certain events, such as pregnancy and tumorigenesis, which results in either thinner or discontinuous coverage by the outer layer of MECs. Because of this, the MEC layer serves as an epithelial “gatekeeper,” by generating boundaries that help organize breast tissue. A recent paper looks at this gatekeeper function of MECs and finds that two proteins, SLIT and ROBO2, are important in regulating the proliferation of MECs. And, in turn, the growth of the MEC layer regulates the branching of mammary tissue. Image above shows mammary tissue in normal (left) or Robo mutant (right) mice. The loss of Robo leads to excessive branching (close-up views of boxed regions on bottom).
Macias, H., Moran, A., Samara, Y., Moreno, M., Compton, J., Harburg, G., Strickland, P., & Hinck, L. (2011). SLIT/ROBO1 Signaling Suppresses Mammary Branching Morphogenesis by Limiting Basal Cell Number Developmental Cell, 20 (6), 827-840 DOI: 10.1016/j.devcel.2011.05.012
Copyright ©2011 Elsevier Ltd. All rights reserved.