Chinese researchers have found that a protein secreted by deadly tumour cells may help fight Alzheimer's disease. The team from Huazhong University of Science and Technology in Wuhan discovered that cystatin C, a protein from cancer cells, reduces amyloid plaques in mouse models of Alzheimer's. "We show that cystatin C secreted from peripheral tumour cells effectively reduces amyloid plaque burden and rescues cognition in mouse models of [Alzheimer’s disease]," the scientists wrote in their paper published on January 22 in the journal Cell. Alzheimer’s disease and cancer both commonly affect older people, but it is rare to find a person suffering from both at the same time. This new finding may explain why cancer patients are less likely to develop Alzheimer's disease. The research could open new doors for precision-targeted treatment of the most common form of dementia.