Cancer May Help To Protect Us From Dementia

Dementia has been the leading cause of death in England and Wales for years now. Meanwhile, cancers are responsible for over a quarter of all deaths in the UK.

But, the journal Nature said, researchers have noticed that the two conditions are rarely seen in the same person. Cancer survival has previously been linked to an 11% decrease in dementia risk, and dementia has been associated with a 25% lower cancer risk.

That “decades”-long observation led some to think that one disease might have a protective effect on the other. 

And now, new research published in Cell has found a protein that might explain that link.

Why might cancer help to protect us from dementia? 

At the start of the 15-year-long study, researchers tried to work out how to model the effects of cancer on dementia in mice.

They found that, in mouse models of dementia, human lung, prostate and colon tumour transplants seemed not to develop Alzheimer’s, despite being primed to do so. 

So, they spent years trying to work out why that happened. They wanted to see which parts of the cancer cells were able to cross the blood-brain barrier, possibly affecting the accumulation of amyloid plaques linked to dementia.

After six years, they identified a protein called cystatin C, which both crossed the blood-brain barrier and appeared to link to the molecules that form those harmful plaques. 

Once there, they activate another protein called TREM2, which signals the brain to send patrolling immune cells that break those plaques down. 

That means the protein present in cancer cells could help to break protein clumps linked to dementia apart.

What could this mean? 

The paper said that this might “provide significant conceptual advances into cancer neuroscience,” and could help to shift how we treat dementia-linked amyloid plaque accumulation in the brain.

Instead of trying “amyloid-lowering strategies”, the findings from this research could work by “degrading the existing amyloid plaques” in “targeted” therapy.

This is only a part of the puzzle, Nature said. Not all dementias appear to be caused by amyloid plaque formation, for instance.

But it’s an “interesting” finding.