Stem cells replenish our tissues with new cells as and when they're needed. But over-production of cells when they’re not required can lead to cancer. One example is found in the mammary glands – more commonly known in humans as breasts – where stem cells produce tree-like milk ducts. Mammary stem cells are remarkably potent, and a single cell can recreate an entire duct tree. This picture shows a milk duct tree grown from breast duct cells, which have been converted into stem cells by the addition of two specific proteins. The duct cells have been labelled with a fluorescent ‘marker’ protein, making them glow green under an ultraviolet-light microscope and revealing the delicate, branching structure. This impressive regenerative capacity also has a dark side – researchers think that the proteins responsible for maintaining mammary stem cells may also fuel the growth of some breast cancers.
Written by Kat Arney
BPoD stands for Biomedical Picture of the Day. Managed by the MRC London Institute of Medical Sciences the website aims to engage everyone, young and old, in the wonders of biomedicine. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.