Stem Cell Defects May Cause Breast Cancer

The onset of breast cancer may be caused by defects in somatic adult stem cell niches that exist long before a tumor develops, according to researchers at the Lombardi Comprehensive Cancer Center of Georgetown University (Washington, DC, USA).

The research built on prior findings that demonstrated the existence of five different types of cells in normal breast cancer tissue. Two are stem cell-like and give rise to the other three. For the current study, all cell types were identified at low magnification, allowing more cells to be counted. Not only did each cell population have a different size in normal breast tissue but the cells are arranged in particular relationships to each other. These form repeating units called stem cell niches and provide microenvironments that house the adult stem cells and their daughter cells.

In mice that expressed excess amounts of either of the cancer-producing proteins, the size of the cell populations changed in relation to each other. The order of the cell arrangements was disrupted in the stem cell niches of mice with breast cancer, showing that each cell population may play a different role in the development of breast cancer and that the environment in which a cell grows can influence its chance of becoming cancerous.

"The results also show how complicated cancer is as a disease,” said lead author Gloria Chepko, Ph.D., a postdoctoral fellow at the Lombardi Comprehensive Cancer Center. "Although it's not something that will be solved easily or quickly, our study reveals important information on the genesis of breast cancer in the body.” The findings were reported in the October 2005 issue of Tissue and Cell.




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Lombardi Comprehensive Cancer Center