Researchers have developed a groundbreaking new way to grow breast tissue in a petri dish.

The research team developed an assay in which cultured human breast epithelial cells were used to rebuild the tissue architecture of the mammary gland, the German Research Center for Environmental Health reported.

They used a transparent gel in which cells divide and spread the way they would in the mammary gland during puberty. Eventually, they create hollow ducts that create a network of branches that terminate in grape-like structures. Breast tissue is constantly being remodeled through to ensure milk production. This means that the cells must have a high regenerative capacity, but breast cancer cells can adapt to this property and acquire aggressive traits. This new method could help determine exactly how these aggressive traits arise in breast cancer cells.

The researchers used the new assay to observe the behavior of regenerative cells and found the regenerative capacity was determined by the physical properties of the surrounding environment.

"We were able to demonstrate that increasing rigidity of the gel led to increased spreading of the cells, or, said differently, invasive growth. Similar behavior was already observed in breast cancer cells. Our results suggest that invasive growth in response to physical rigidity represents a normal process during mammary gland development that is exploited during tumor progression," said Jelena Linnemann

"With our assay, we can elucidate how such processes are controlled at the molecular level, which provides the basis for developing therapeutic strategies to inhibit them in breast cancer," first author of the study Co-author Lisa Meixner added.

The findings were published in a recent edition of the journal Development.