USC study shows how tumor cells in the bloodstream can target distant organs

Various types of cancer can become particularly aggressive and difficult to treat once they spread from their initial point of origin to other parts of the body. This unfortunate phenomenon, known as metastasis, can make treatment very challenging, decreasing the chance of survival for the patient.

In order to better understand this process, a CIRM supported study at USC looked at breast cancer cells circulating in the blood that eventually invade the brain. The findings, which appear in Cancer Discovery, shed light on how tumor cells in the blood are able to target a particular organ, which may enable the development of treatments than can prevent metastasis from occurring.

Dr. Min Yu

Dr. Min Yu and her lab at USC were able to isolate breast cancer cells from the blood of breast cancer patients whose cancer had already metastasized. The team then expanded the number of cancer cells through a process known as cell culture. These expanded human tumor cells were then injected into the bloodstream of animal models. It was found that these cells migrated to the brain as was predicted.

Upon further analysis, Dr. Yu and her lab discovered a protein on the surface of the tumor cells in the bloodstream that enable them to breach the blood brain barrier, a protective layer around the brain that blocks the passage of certain substances, and enter the brain. Additionally, Dr. Yu and her team discovered another protein inside the tumor cells that shield them from the brain’s immune response, enabling these cells to grow inside the brain.

In a news release in Science Magazine, Dr. Yu talks about how these findings could be used to improve treatment and prevention options for those with aggressive cancers:

“We can imagine someday using the information carried by circulating tumor cells to improve the detection, monitoring and treatment of the spreading cancers. A future therapeutic goal is to develop drugs that get rid of circulating tumor cells or target those molecular signatures to prevent the spread of cancer.”

CIRM has also funded a separate clinical trial related to the treatment of breast cancer related brain metastases.