Researchers have identified specific cellular and molecular changes that occur after a stroke and appear to drive the growth of glioma, the most common and aggressive form of malignant brain tumor in adults. The study offers a possible explanation for a long-observed but poorly understood link between brain injury and cancer.
Previous work has estimated that patients with a history of stroke or traumatic brain injury can be at a 3x to 7x increased risk for developing brain tumors, depending on the age and sex of the patient.
For the study, published in Nature Cancer, researchers focused on one type of brain injury—stroke—and on a specific type of brain tumor—glioma—which has a 5-year survival rate.
The team discovered the emergence of a distinct population of brain cells—tumor-associated astrocytes (TAAs) —with distinct physiological and molecular characteristics, including diminished calcium activity. TAAs were accompanied by the accumulation of two other cell types, remodeled tumor-associated microglia and immune cells called macrophages (TAMs).
Restoring TAA calcium signaling or removing TAMs suppressed stroke-induced glioma progression, identifying both populations as critical mediators of the stroke response. The findings suggest that these injury-induced, tumor-promoting pathways are potential therapeutic targets and support continuing research into strategies that could reduce the risk of glioma growth in patients with a history of brain injury.
The researchers say the injury-induced pathways they identified represent potential therapeutic targets and support continued research into strategies that could reduce the risk of glioma growth in patients with a history of brain injury, potentially opening a new avenue for preventing or slowing tumor development following stroke.
“Our study supports that brain injury can be a risk factor for brain cancer. In addition, our findings contribute to growing evidence pointing at a role of astrocytes in brain tumor growth,” said corresponding author Hyun Kyoung Lee, associate professor of pediatrics-neurology at Baylor. “Neuron-tumor interactions have been shown to contribute to cancer growth. We show that other brain cells, astrocytes, also seem to communicate with brain cancer cells and influence their behavior. They should be considered when studying cancer mechanisms and therapies.”
Data from Baylor College of Medicine