Don’t forget your helmet when cycling, skiing and (of course) motorcycling. In addition to increasing the risk of early death, head trauma can put patients at a four times higher risk of glioma according to a study from University College London Cancer Institute published in the journal Current Biology on February 24, 2023.
Brain damage may promote glial cell transformation
Glioma is a rare but aggressive type of brain cancer. It occurs in glial cells such as astrocytes. However, these are considered “less likely to cause tumours”explain researchers from the University College London Cancer Institute in a communiqué. “However, recent findings have demonstrated that following injury, astrocytes can once more exhibit stem cell behavior”more prone to becoming cancerous, they note.
The scientists thus wanted to verify whether these glial cells were capable of forming a tumor following a brain trauma. To do this, they injected mice with brain damage with a substance that marked astrocytes and deactivated the gene called p53, known to play a protective role once morest many cancers. A control group also injured in the head still had an intact p53 gene while other rodents without trauma had an inactive p53 gene.
The head of research, Prof. Simona Parrinello, remarks: “Normally astrocytes are highly branched, but what we found was that without p53 and only following injury, astrocytes had their branches retracted and become more rounded. They weren’t quite like stem cells, but something had changed, so we let the mice age, then looked at the cells once more and saw that they had completely returned to a rod-like state with early glioma cell markers which might be divided”.
According to her, this suggests that mutations in certain genes synergize with brain inflammation induced by head injury. This phenomenon increases with time during aging to ultimately make astrocytes more susceptible to initiating cancer.
Head trauma: a risk of brain tumor 4 times higher
To test their hypothesis, the team consulted the medical records of more than 20,000 patients with traumatic brain injuries. The researchers found that people who had suffered a head injury were almost four times more likely to develop brain cancer later than uninjured individuals.
Professor Parrinello says: “We know that normal tissues carry many mutations that appear to have no major effects. Our results suggest that if, in addition to these mutations, injury occurs, it creates a synergistic effect”. She notes that in the young injured brains studied, inflammation was still relatively low, despite the injury. However, with aging, inflammation appears to worsen over time, particularly at the level of the lesion. “It can reach a certain threshold following which the mutation begins to manifest“, thus favoring the appearance of cancer, she concludes.
“It is important to keep in mind that the risk of developing brain cancer is low overall, estimated at less than 1% over a lifetime, so even following injury the risk remains modest”reassure the scientists at the end of their study.
