Scientists, for the first time, have successfully identified and isolated adult mammary stem cells in mice which may later be used to regenerate breast tissue.
The Fred Hutchinson Cancer Research Center research may also provide better understanding of the role of adult stem cells in breast cancer development, and develop potential new targets for anti-cancer drugs.
Using a genetically modified mouse model, the researchers tagged stem cells with green fluorescent protein (GFP), which exhibits bright green fluorescence during gene expression and can be easily seen under a microscope.
"Until now, we have not been able to identify stem cells in mammary tissue. They have never been detected before with such specificity. It is extraordinary. You can see these green stem cells under the microscope in their pure, natural state," said Larry Rohrschneider of the Hutchinson Center.
The researchers demonstrated the presence of active green stem cells at crucial stages of mammary development, such as puberty and pregnancy. During quiescent stages of development, however, the cells did not "light up."
Such stem cells represent a new alternative to induced pluripotent stem cells, or genetically altered stem cells, for various medical applications.
"We have found that those transplanted green stem cells can generate new mammary tissue and this tissue can produce milk, just like normal mammary epithelial cells," said co-author Lixia Bai.
"Identification of the exact stem cell and its location is the first critical and fundamental step toward understanding the regulatory mechanisms of these important cells," she said.
The findings appeared in Genes and Development.