Researchers at Boston Children’s Hospital have discovered that Alzheimer’s disease may be driven by cancer-associated genetic mutations in immune cells, according to a study published in the journal Cell. By analyzing brain and blood tissue, the team found that mutated immune cells—specifically microglia—penetrate the brain and trigger inflammation, suggesting that existing cancer therapies could potentially be repurposed to treat the neurodegenerative condition.
Why do immune cells develop cancer-like mutations in the brain?
As the body ages, cells naturally accumulate genetic changes. According to Dr. Christopher Walsh, lead author and Chief of the Division of Genetics and Genomics at Boston Children’s Hospital, microglia—the brain’s primary immune cells—begin to harbor mutations in genes typically linked to blood cancers like lymphoma and leukemia. These mutations provide the cells with a biological advantage, allowing them to multiply more aggressively than healthy cells when they encounter the protein clumps associated with Alzheimer’s disease.
Scientists previously believed microglia were permanent brain residents that never crossed the blood-brain barrier. This new research suggests that aging or injury can breach that barrier, allowing mutant immune cells from the bloodstream to infiltrate the brain and transform into microglia-like cells.
How do these mutations affect Alzheimer’s progression?
The study, which examined 149 cancer-driving genes in 190 Alzheimer’s patients and 121 healthy controls, found that these mutated cells create a highly inflammatory environment. Dr. August Yue Huang, a collaborator on the study, noted that this mechanism represents a shift in how researchers view Alzheimer’s pathogenesis. The inflammation caused by these “mutant” cells damages nearby neurons, which directly contributes to the cognitive decline observed in patients.
Could blood tests replace invasive brain diagnostics?
Because accessing brain tissue in living patients is difficult, researchers are looking toward blood-based screening. Dr. Alice Eunjung Lee suggests that if these mutations are present in the blood, they could serve as a biomarker for Alzheimer’s risk. A recent preprint analysis by Huang and Lee found that these cancer-driver mutations appear to increase Alzheimer’s risk independently of the APOE4 gene, which has long been considered the primary genetic risk factor for the disease.
| Factor | Impact on Alzheimer’s |
|---|---|
| APOE4 Gene | Established, high-risk genetic marker. |
| Cancer-Driver Mutations | Newly discovered risk factor; acts independently of APOE4. |
Frequently Asked Questions
Can cancer drugs treat Alzheimer’s disease?
According to Dr. Walsh, because the mutations driving the inflammation in Alzheimer’s brains are the same as those in certain blood cancers, some existing cancer drugs might be repurposed to target these specific cells.
Is this mutation inherited?
No. The research describes these as somatic mutations, meaning they are acquired over a person’s lifetime rather than inherited from parents.
How does the blood-brain barrier play a role?
The researchers propose that aging or injury weakens the blood-brain barrier, which allows immune cells circulating in the blood to enter the brain and contribute to the disease process.
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This research was supported by the Howard Hughes Medical Institute, the National Institute on Aging, the NIH Common Fund, and the Suh Kyungbae Foundation.
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