During puberty the mammary gland forms a network of milk-ducts that are repeatedly reshaped through a woman’s life to allow her to provide milk for any children she may have. But the regenerative processes that enable this to happen are poorly understood. Unravelling them could help us better tackle breast cancer as it is the cells of this mammary gland network that usually go awry.

Christina Scheel at the Helmholtz Centre for Health and Environmental Research in Munich and her team took mammary gland cells from donated human tissue and added them to gels made of collagen fibres, a common type of connective tissue. The cells spread out and connected to these fibres, pulling on them. This generated a physical force that enabled the cells to grow into a new mammary gland network inside the Petri dish.