Some Skin Cancers Tied to Lower Odds of Alzheimer's
A weak immune response might allow skin cancer but protect brain from inflammation, expert suggests
Others think the link may be directly related to how the lowered immune response of skin cells in skin cancer corresponds to a similar immune response in the brain.
"This research is another piece of evidence that tells us that peripheral inflammation [in the skin] is very important in Alzheimer's disease," Town said. He thinks that people who develop non-melanoma skin cancers don't have an immune response in their skin, and thus develop skin cancers, because an immune response may be critical to fighting skin cancer. But that benefits them when it comes to developing Alzheimer's disease.
"This reduced inflammatory response that was permissive to the skin cancer was perhaps beneficial in the brain," said Town.
Town thinks the study suggests a fascinating and important concept: skin cancer may be a biomarker for resistance to Alzheimer's disease. That means, for example, that it may be possible that drugs that dampen the inflammatory response, such as a TNF-alpha inhibitor, could potentially be used to help prevent Alzheimer's disease.
TNF-alpha inhibitors block TNF-alpha, a protein that is present in larger quantities in people who have certain inflammatory conditions, such as rheumatoid arthritis, Crohn's disease and psoriasis. TNF-alpha inhibitors include adalimumab (Humira), etanercept (Enbrel) and infliximab (Remicade).
The latest research involved 1,102 people in New York City, whose average age was 79 when they enrolled in the study. None of the participants had dementia at the beginning of the study. Every year, a team tested them for memory, concentration, language, planning abilities and other factors. During the average four-year follow-up, they were asked annually whether they had developed non-melanoma skin cancer.
At the start of the study, 109 people reported that they had been diagnosed with skin cancer in the past. During the study, 32 people developed skin cancer and 126 people developed dementia, 100 of those with Alzheimer's. Of the 141 people with skin cancer, only two developed Alzheimer's disease, compared to 98 of the 961 people without skin cancer.
Alzheimer's is the most common form of dementia, defined by declines in memory and other thinking abilities.