A stroke may make the most common type of adult brain cancer grow faster and spread further, according to new research in human and mouse models
The study examined how stroke may influence glioma, a type of brain tumour described by the researchers as the most prevalent and aggressive malignant brain tumour in adults.
Stroke was also associated with reduced overall survival in the models studied.
The work was carried out by researchers at Texas Children’s Duncan Neurological Research Institute, Baylor College of Medicine and collaborating institutions.
Corresponding author Dr Hyun Kyoung Lee said previous epidemiological and clinical studies had suggested that people with a history of stroke or traumatic brain injury may have an increased risk of developing brain tumours.
Lee said: “Epidemiological and clinical studies suggest that patients with a history of stroke or traumatic brain injury are at increased risk of developing brain tumours.
“The risk can be about three-fold to seven-fold, depending on the age and sex of the patient.”
The researchers focused on stroke and glioma to investigate whether stroke promotes glioma growth and the possible biological mechanisms connecting brain injury and cancer.
They identified a distinct population of tumour-associated astrocytes, or TAAs, with altered physiological and molecular characteristics, including reduced calcium activity.
The TAAs were accompanied by an accumulation of remodelled tumour-associated microglia and immune cells called macrophages.
Restoring calcium signalling in the tumour-associated astrocytes or removing the tumour-associated macrophages suppressed stroke-induced glioma progression in the experimental models.
The researchers identified both cell populations as critical mediators of the response to stroke and said the pathways involved could be potential therapeutic targets.
Lee said: “We show that stroke promoted tumour infiltration into injured brain regions in human and mouse glioma models, and reduced overall survival. Looking closer into the cellular and molecular makeup of the tumours, we found that stroke triggers remodelling of the tumour microenvironment.”
The researchers said the findings support further investigation of strategies that could reduce the risk of glioma growth in people with a history of brain injury.
Lee said: “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 tumour growth.
“Neuron-tumour 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 behaviour. They should be considered when studying cancer mechanisms and therapies.”
