Inverse Association between Cancer and Dementia of the Alzheimer’s Type

With increasing life expectancy there is also a concomitant increase in the prevalence of agerelated disorders, including neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, and various cancers. Here we report findings suggesting that there is an inverse relationship between development of dementia of the Alzheimer type and a history of cancer. The inverse relationship was found when all cancer types were analyzed and also when skin cancers (both benign and melanomas) were analyzed separately. We discuss possible explanations for this inverse relationship, among them, the possibility that a common biological mechanism might be regulated in opposite directions in neurodegenerative diseases and cancer.