Localized Breast Cancer Cells Have Potential to Spread

Early breast cancer tumors that have not yet spread contain cells with a predisposition to migrate to new tissue, a new study finds.
So, just because a cancer has not yet spread doesn't mean its cells lack the ability or inclination to do so, warned researchers at the Salk Institute for Biological Studies in La Jolla, Calif. They added that there is also no evidence to suggest that these cells correlate with a positive or negative health outcome for women with breast cancer.
"This is an exciting finding, because it suggests that cells might acquire migratory properties much earlier than expected," senior author Tony Hunter, a professor in the Molecular and Cell Biology Laboratory at the institute, said in a prepared statement.
Self-screening for breast cancer, regular doctor's visits and mammograms have all made it possible to identify breast cancer tumors in their early stages. When identified early, the cancer cells usually are within the confines of a milk duct, the most common origin of breast cancer tumors.
Removal of the small tumor and surrounding tissue, called a lumpectomy, is the standard treatment for this early stage of breast cancer. The question of whether women should also have radiation treatment to address any stray cancer cells has been hotly debated, partly because approximately 16 percent of these patients will see their cancer return within five years.
According to the researchers, the identification of cells that could spread, called motile cells, supports the need for radiation, which is usually determined by tumor size.
The research team studied breast cancer in the lab by allowing breast tissue to grow under observation. The researchers also turned on a series of chemical signals, called the ERK1/2 MAP kinase pathway, that is often active during tumor growth. They then watched as breast cancer cells began to grow and become more aggressive.
The lab setting limited the spreading of the cancer cells, but the researchers interpreted the activity of the cells to indicate a potential for spread.
Writing in the current edition of The Journal of Cell Biology, the researchers said the next step is to identify biological markers to help oncologists diagnose patients who are at higher risk of metastasis.