Cancer survival has previously been linked to an 11% decrease in dementia risk, and dementia has been associated with a 25% lower cancer risk. Why might cancer help to protect us from dementia? At the start of the 15-year-long study, researchers tried to work out how to model the effects of cancer on dementia in mice. They wanted to see which parts of the cancer cells were able to cross the blood-brain barrier, possibly affecting the accumulation of amyloid plaques linked to dementia. AdvertisementThat means the protein present in cancer cells could help to break protein clumps linked to dementia apart.