Ninety percent of cancer-related deaths occur from cancer metastasizing — or spreading — to other areas of the body. If patients with breast cancer die, it is typically due to the cancer spreading to other parts of their body, and not from the specific breast cancer itself.
One of the most dangerous areas that breast cancer could spread to is the brain. The development of brain cancer is seen in about 40% of women that are initially diagnosed with breast cancer, particularly in those with HER2-positive breast cancer.
A research team at City of Hope has now found the mechanisms underlying this metastisis.
“More women than ever are surviving breast cancer only to die from breast tumors growing in their brains years after they’ve been declared cancer-free,” said Dr. Rahul Jandial, a neurosurgeon and researcher at City of Hope.
In order to understand why this is happening, the team took brain tissues samples and compared them to cancerous breast tissue samples.
Findings showed that breast cancer cells can disguise themselves by wrapping in a protein called Reelin. Reelin is typically found in the brain, so by enveloping themselves in this protein, the cancerous cells are able to enter the brain without the brain identifying the cells as enemy.
“The cells are essentially able to act as spies that look like citizens. They release a mesh of protein and escape the brain’s natural defense weapons, causing tumors to grow in the brain.”
Patients diagnosed with brain cancer typically only have a 20 percent chance of surviving. Understanding the mechanisms underlying the way cancer metastasizes is only the first step in developing effective treatments.