For many years, scientists have searched for the causes of Alzheimer’s disease. Most attention has focused on abnormal protein deposits that build up inside the brain.
These protein clumps are considered one of the main signs of the disease.
However, a new study suggests that another process may also be involved, and it comes from an unexpected place: the same genetic mutations that help cause certain cancers.
The study, published in Cell, was conducted by researchers at Boston Children’s Hospital together with collaborators from Harvard Medical School and the Broad Institute.
Their findings suggest that some immune cells involved in Alzheimer’s disease may carry mutations that are commonly linked to blood cancers.
Alzheimer’s disease affects memory, learning, reasoning, and behavior. It is the leading cause of dementia worldwide and becomes more common as people age. Despite decades of research, there is still no cure. Scientists continue to investigate why the disease develops and how it progresses.
One fact about aging is that cells gradually accumulate mutations in their DNA. Most mutations do not cause obvious problems.
However, some provide cells with advantages that allow them to grow or survive better than neighboring cells. In cancer, these mutations can eventually lead to uncontrolled growth.
Researchers wanted to know whether similar mutations might be present in brain immune cells known as microglia. These cells are essential for maintaining brain health. They remove dead cells, clear away debris, and respond to injury and infection. Without microglia, the brain would struggle to maintain its normal functions.
To investigate, the scientists analyzed brain tissue samples from 190 people who had Alzheimer’s disease and compared them with tissue from 121 people without the disease. They focused on 149 genes that are well known for their involvement in cancer.
The results were unexpected. Brain samples from people with Alzheimer’s contained more genetic mutations than healthy samples. Many of the mutations appeared repeatedly in a handful of genes that are often altered in blood cancers.
This raised an intriguing possibility. Could cells carrying these mutations be coming from outside the brain? To test the idea, researchers examined blood samples from individuals with Alzheimer’s disease.
To their surprise, they found the same mutations in blood immune cells. This suggested a possible connection between the blood and the brain that had not been fully appreciated before.
Scientists believe the explanation may involve the blood-brain barrier. This barrier normally acts like a security system, controlling which substances and cells can enter the brain. As people age, or when disease develops, the barrier may become less effective. This could allow certain immune cells from the bloodstream to enter brain tissue.
Once inside the brain, these cells may begin behaving like microglia. If they carry mutations that help them survive and multiply, they may gradually increase in number. Meanwhile, the protein accumulations seen in Alzheimer’s disease may encourage these cells to become even more active.
The researchers propose that these mutated immune cells may produce stronger inflammatory responses than normal microglia. Chronic inflammation is already believed to play an important role in Alzheimer’s disease. Therefore, the presence of these altered cells could potentially accelerate damage to neurons and worsen cognitive decline.
One of the most exciting aspects of the discovery is its possible medical impact. If cancer-related mutations can be detected through blood tests, doctors may one day be able to identify people at increased risk of Alzheimer’s disease before major symptoms appear.
The findings also raise the possibility of using existing cancer drugs in new ways. Because many of the mutations are already well studied in cancer research, scientists may be able to explore whether some therapies can target these abnormal immune cells and reduce their harmful effects in the brain.
The researchers later reported additional evidence supporting the link between these mutations and Alzheimer’s risk. Their follow-up work suggested that the mutations increased risk independently of APOE4, one of the best-known genetic risk factors for Alzheimer’s disease.
Although the study is highly innovative, important questions remain. Researchers still need to prove exactly how these mutated cells contribute to disease and whether reducing their numbers can improve outcomes. Large clinical studies will be required before any new tests or treatments become available.
Even so, the findings represent one of the most unusual and potentially important developments in Alzheimer’s research in recent years. They suggest that Alzheimer’s disease may share biological features with cancer in ways that were previously unrecognized.
By bringing together knowledge from neurology, genetics, immunology, and cancer research, scientists may have uncovered a new pathway that could eventually lead to better diagnosis and treatment options.
The study offers a fresh perspective on a devastating disease and opens the door to entirely new areas of investigation.
If you care about Alzheimer’s disease, please read studies about vitamin D deficiency linked to Alzheimer’s and dementia, and strawberries can be good defence against Alzheimer’s.
For more health information, please see recent studies about foods that reduce Alzheimer’s risk, and oral cannabis extract may help reduce Alzheimer’s symptoms.
