Dementia and cancer are two of the diseases people fear most as they grow older.
Although they seem completely different, researchers have noticed for decades that they do not often appear together in the same person.
This unusual pattern has puzzled scientists around the world. A new study from the University of Kentucky Sanders-Brown Center on Aging may finally explain part of the mystery.
The researchers studied a gene known as GRN, which contains instructions for making a protein called progranulin.
This protein is involved in many important jobs inside the body, including cell growth, tissue repair, and inflammation. Because it influences so many biological processes, scientists suspected that it might affect several diseases at once.
Their study focused on a common DNA variation called rs5848. After analysing genetic information, the team discovered that this single genetic change was linked with a greater chance of developing LATE dementia while at the same time being linked with a lower chance of developing cancer.
Their findings were published in the Journal of Neuropathology & Experimental Neurology.
LATE is a form of age-related dementia that affects roughly one in four people older than 85. Many people have never heard of it because its symptoms look very similar to Alzheimer’s disease. People with LATE often experience memory loss, confusion, and difficulty thinking clearly, making diagnosis challenging without detailed examination.
The discovery helps explain earlier research showing that people with cancer often have fewer signs of dementia in their brains. Scientists now believe that progranulin could be one reason for this opposite pattern. Too much progranulin may encourage cancer cells to grow, while too little may allow damaging brain proteins to accumulate.
Another interesting finding involved ancestry. The researchers found that the dementia-related version of the GRN variant appeared more frequently among Black Americans, while the version linked with lower cancer risk appeared more often among white Americans.
These differences show why diverse populations are essential in medical research and why disease risks can vary between groups.
The findings may also affect future drug development. Several companies are testing medicines that increase progranulin levels to protect brain cells. While these treatments could help slow certain forms of dementia, scientists will also need to study whether raising progranulin could unintentionally increase cancer risk.
The researchers emphasise that genes are only one part of the story. Healthy lifestyle habits, medical care, and other genetic factors also contribute to whether someone develops dementia or cancer.
If you care about dementia, please read studies about dietary strategies to ward off dementia, and how omega-3 fatty acids fuel your mind.
For more health information, please see recent studies about Choline deficiency linked to Alzheimer’s disease, and what to eat (and avoid) for dementia prevention.
The research was published in the Journal of Neuropathology & Experimental Neurology.
