Can Injury to the Brain Lead to Brain Cancer?

Brain trauma can lead to brain cancer, stated a new research article published in Current Biology, by UCL, London. The inflammation after brain injury remodels the mature cells in the brain and turns them cancer prone. The cells that are primarily involved are the astrocytes, i.e., star-shaped mature brain cells which protect the brain. These cells rarely cause cancer. Cancer caused by these cells is called glioma.

Astrocytes are not usually involved in developing brain cancer. But brain injury triggers a cascade of inflammation which in turn changes the genetic structure in the cells and may cause mutations resulting in the development of stem cells. The stem cells give the cell an unlimited potential to divide. These changes primarily occur due to inflammation in the brain cells following injury.

To stop this self-destructive phenomenon, body has a brilliant pathway i.e., the p53 genetic pathway which identifies the destructive mutations in the cells which have carcinogenic potential. After identification, the p53 gene destroys the mutated cells thus protecting the body. The p53 is the most mutated cancer-causing gene sequence (1^✔ ✔Trusted Source
Tumor suppressor p53: Biology, signaling pathways, and therapeutic targeting

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In this experimental study design, researchers have induced injury in one group of mice and further divided this group into two groups research and a control group. In research group, p53 activity was blocked and, in the control, group the p53 activity was left intact. They have studied one more group other than these two in which they have not induced a brain injury but have blocked the p53 group activity to study the changes caused by brain injuries in detail. They used a mechanism to relabel the astrocytes permanently red so that the changes can easily be marked.

P53 thus acts as a gateway for preventing harmful cancer-related changes from occurring in a cell. Keeping this effect in mind the scientists designed the study by observing a group of mice that had blocked p53 to eliminate the bias and to remove the masking effect of p53 on cancer-related changes in the cell.

The group that had induced brain injury and with the blocked p53 gene showed structural and molecular changes leading to genetic remodelling which converted them to stem cells. When a cell reverts to this stage, it will divide without inhibition and can contribute to cancer. The other groups didn't show these changes.

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There was always a curiosity surrounding the relationship between brain injury and brain cancer, but this study has proven this relationship with solid evidence.

Risk Rate for Brain Injury to Turn into Brain Cancer

Then the scientists examined over 20,000 cases of head injuries and assessed them for the risk of brain cancer. The people who suffered brain injury had 4 times higher brain cancer risk compared to the people who did not suffer an injury.

The groups were chosen carefully considering sex, socio demographics differences, age, and comorbidities to eliminate any associated bias in the study.

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The total estimated average risk for brain cancer incidence is 1%. So, when considered that way even four times increased risk after head injury can be considered as a very small risk.

This is what the team lead Dr. Simona Parinello has to say about the experiment and findings. "Normally astrocytes are highly branched – they take their name from stars – but what we found was that without p53 and only after an injury the astrocytes had retracted their branches and become more rounded. They weren’t quite stemming cell-like, but something had changed. So we let the mice age, then looked at the cells again and saw that they had completely reverted to a stem-like state with markers of early glioma cells that could divide.”

Reference:

1. Tumor suppressor p53: Biology, signaling pathways, and therapeutic targeting - (https://pubmed.ncbi.nlm.nih.gov/33932560/)

Source-Medindia