Scientists Explain Mechanism Behind Breast Cancer Relapse

A new study from the Texas A&M College of Medicine revealed a possible explanation why some breast cancer patients experience a more aggressive form of the disease a few months after a successful treatment.

The study, published in the journal Proceedings of the Royal Academy of Sciences, found that tumor cells can become dormant after eating stem cells, a phenomenon called "cancer cells cannibalism". These dormant cancer cells may activate once again, resulting to a more aggressive and difficult to treat breast cancer.

"The breast cancer cells that had taken in the stem cells went dormant-essentially became 'sleepy'-but at the same time they became much more difficult to kill," explained Thomas J. Bartosh, PhD, assistant professor at the Texas A&M College of Medicine and first author of the study, in a press release. "Then one day, when conditions are right, the cells 'wake up' and start growing again, this is when the cancer recurs, and because the cells are treatment-resistant, the recurrence can be very difficult to combat."

Their discovery was made after the researchers, who were trying to teach mesenchymal stem/stromal cells (MSCs) to fight cancer, observed that the stem cells are disappearing from their culture. At first, the researchers thought that they made a mistake or were witnessing an anomaly or negative result. However, further observations revealed that the breast cancer cells are actually devouring the adult stem cells.

The breast cancer cells that ate the stem cells enter dormancy, while also becoming highly resistant to chemotherapy and nutrient deprivation. Additionally, the few numbers of these MSC-eating breast cancer cells make it difficult to detect with the existing scanning methods.

With their findings, the researchers hope to develop a new treatment to prevent the dormant MSC-eating cancer cells from waking up. Another possible treatment to prevent breast cancer relapse include the development of drugs that will prevent breast cancer cells from cannibalizing adult stem cells.