( CNN ) -- Scientists say they `` serendipitously '' discovered that a drug used to treat a type of cancer quickly reversed Alzheimer 's disease in mice . `` It 's really exciting , '' said Maria Carrillo , senior director for medical and scientific relations for the Alzheimer 's Association . `` They saw very positive and robust behavior effects in the mice . '' In the study , researchers at Case Western Reserve University School of Medicine gave mice mega-doses of bexarotene , a drug used to treat a type of skin cancer called cutaneous T-cell lymphoma . Within 72 hours , the mice showed dramatic improvements in memory and more than 50 % of amyloid plaque -- a hallmark of Alzheimer 's disease -- had been removed from the brain . The study was published Thursday in the journal Science . Gary Landreth , the lead researcher at Case Western , cautioned that even though his results were impressive in mice , it may turn out not to work in people . `` I want to say as loudly and clearly as possible that this was a study in mice , not in humans , '' he said . `` We 've fixed Alzheimer 's in mice lots of times , so we need to move forward expeditiously but cautiously . '' Mice -- and humans -- with Alzheimer 's have high levels of a substance called amyloid beta in their brain . Pathology tests on the mice showed bexarotene lowered the levels of amyloid beta and raised the levels of apolipoprotein E , which helps keep amyloid beta levels low . Landreth said he hopes to try the drug out in healthy humans within two months , to see if it has the same effect . Those participating in the trial would be given the standard dose that cancer patients are usually given . Researchers tested the memories of mice with Alzheimer 's both before and after giving them bexarotene . For example , the Alzheimer 's mice walked right into a cage where they 'd previously been given a painful electrical shock , but after treatment with bexarotene , the mice remembered the shock and refused to enter the cage . In another test , the scientists put tissue paper in a cage . Normal mice instinctively use tissues in their cage to make a nest , but mice with Alzheimer 's ca n't figure out what to do with the tissues . After treatment with the drug , the Alzheimer 's mice made a nest with the paper . Carrillo said one of the major advantages of bexarotene is that it 's already been approved by the Food and Drug Administration for use in humans , which means the researchers can move into human trials sooner than if it were a completely new drug . The Alzheimer 's Association is funding Case Western 's next phase of research , which will involve using bexarotene at the levels used on cancer patients , Landreth said . Since the drug does have some side effects -- it can increase cholesterol , for example -- he hopes to use it in even lower levels as the study goes on . Landreth said his lab had been working on other drugs for Alzheimer 's for 10 years when a graduate student , Paige Cramer , decided to try bexarotene , which works on a receptor involved in amyloid beta clearance . Some other drugs that worked in mice were too toxic to use in humans . `` We 're really lucky that bexarotene is a great drug with an acceptable safety profile , '' he said . `` This does n't happen very many times in life ' '' CNN 's William Hudson contributed to this report .
`` They saw very positive and robust ... effects in the mice , '' an Alzheimer 's official says . Researchers found improvements in mice 's memories after they got the drug . The lead researcher cautions that not all good results in mice are seen in humans .