Is there a link between cancer and Alzheimer disease?

Cancer and Alzheimer disease (AD) are common age-related conditions. Cancer arises from dysfunction of genetic and epigenetic processes that control cellular differentiation and proliferation. Recent data suggest that molecular machinery that is involved in maintaining neural function in neurodegenerative disease may be shared with oncogenetic pathways. For example, some studies suggest that cancer incidence is lower among persons with Parkinson disease.1 Few data are available regarding a link between cancer and AD.2 However, the presence of an association could further stimulate investigations related to molecular changes underlying neurodegenerative diseases. In this issue of Neurology ®, Roe et al.3 use data from the Cardiovascular Health Cognition Study to investigate the relationship between cancer and AD. The Cardiovascular Health Study is a population-based cohort study of nearly 5,900 persons. The Cognition Study is an ancillary study of about 3,600 persons who had an MRI brain scan and completed annual brief cognitive testing for up to 5 years. Several years later, subjects were divided into high- and low-risk groups for dementia based on cognitive tests available in the Cardiovascular Health Study. A sample of surviving high-risk white subjects, and all minorities, were invited to participate in a clinical evaluation. Medical records were obtained for deceased participants and those who refused the evaluation. …